NZASE #125

science teacher 2010

Featuring: Nitrogen Nitrogen in foods Nitrogen, soils and the NZ environment Reactive nitrogen in the environment Agricultural nitrous oxide emissions Global nitrogen cycle Plus: Science and “Creative Destruction�

Teaching controversial issues in science Futures focus in science classrooms Allan Wilson and Out of Africa model

Number 125

ISSN 0110-7801

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Editorial 2 From the President’s desk 3 Feature: Nitrogen Nitrogen in foods 13

Editorial Address: lyn.nikoloff@xtra.co.nz Editorial Board: Rosemary Hipkins, Chris Joyce, Suzanne Boniface, Beverley Cooper, Mavis Haigh, Barbara Benson, Miles Barker and Anne Hume

Nitrogen, soils and the NZ environment 16

Journal Staff: Editor: Lyn Nikoloff Sub editor: Teresa Connor Cover Design and Typesetting: Pip’s Pre-Press Services, Palmerston North Printing: K&M Print, Palmerston North Distribution: NZ Association of Science Educators

Agricultural nitrous oxide emissions 22

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Subscription includes membership and one copy of NZST per issue (i.e. three copies a year). All prices are inclusive of GST. Please address all subscription enquiries to the NZASE, PO Box 1254 , Nelson 7040. Subscriptions: nzase@confer.co.nz Advertising: Advertising rates are available on request from nzst@nzase.org.nz Deadlines for articles and advertising: Issue 126 - 20 January 2011 (publication date 1 March)

NZST welcomes contributions for each journal but the Editor reserves the right to publish articles it receives. Please contact the Editor before submitting unsolicited articles: nzst@nzase.org.nz Disclaimer: The New Zealand Science Teacher is the journal of the NZASE and aims to promote the teaching of science, and foster communication between teachers, scientists, consultants and other science educators. Opinions expressed in this publication are those of the various authors, and do not necessarily represent those of the Editor, Editorial Board or the NZASE. Websites referred to in this publication are not necessarily endorsed.

Reactive nitrogen in the environment... 19 Global nitrogen cycle 26 Allan Wilson Lecture Allan Wilson and testing the Out of Africa model for human origins 8 Regular features Education research: Teaching and learning about controversial science issues 30 Introducing and expanding a futures’ focus in science classrooms 34 Science education a vehicle for the key competencies in praxis 38 History Philosophy of Science: Science and “Creative Destruction” 4 Resources: Ask-a-scientist 7, 12, 15, 25, 33 ANZCCART 12 Subject Associations: Comment from SciCon 41 Biology 42 Primary Science 43, 44 Chemistry 45 Physics 46 Science/PEB 47 Technicians 48

Front cover: Pohangina River, Manawatu.

Photograph courtesy of Lyn Nikoloff.

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more reflections...

There seems to be a mantra running through the halls of education policy making that if we don’t change it, whatever it happens to be, we just might be left “behind”!

So I read with interest an opinion piece in this issue by Robert Shaw (page 41) about the nature of science. I mention this because there seems to be a mantra that ‘nature of science’ is the newest best thing about science, akin to a new best friend. Yet I wrote about this very issue in a Master’s Thesis in 2000, and over the past four years, Philip Catton has been delivering the equivalent of a post graduate paper on the topic. Sadly, in this issue he wraps up his excellent series by commenting on science, education and the NZST (page 4).

Back to changes…we live in a culture that values little but the moment – the collective memory is no longer than an iTune, and if it can’t be viewed on YouTube or talked about on Facebook then it, whatever it is, has no currency. And rather than railing against the tide of sound bite education, somehow it is believed that it should be embraced.

So what is the future of general science, which the Thomas Committee introduced into our core curriculum in 1942? It seems that science education is again under the microscope. I call it the ‘seven year itch’ but we need look no further than our colleagues in the scientific community to see how the economy and political climate impacts on change. Gone, it seems to me, are the days of multidiscipline teams, collegiality and idle curiosity about all things great and small.

In this issue, I commend to you articles about nitrogen, all of which exemplify good science carried out by scientists who are knowledgeable, curious and persistent: nitrogen in food – Alistair Carr (p. 12); nitrogen soils and the environment – Louis Schipper and Graham Sparling (p.16); reactive nitrogen in the environment – Scott Fraser (p.19); agricultural nitrous oxide emissions – Donna Giltrap and Surinder Saggar (p.22); and global nitrogen cycle – Mike Harvey (p. 26).

I also commend to you an article about Allan Wilson and human origins (page 8) written by Professor David Penny.

Also in this issue we feature education research articles about: teaching and learning about controversial science issues – Kathy Saunders (p.30); a futures focus in our classrooms – Cathy Buntting (p.34); and key competencies in praxis – Steve Sexton (p.38). Plus we feature all of your regular subject association reports.

So there you have it…another great rollicking read from the scientific and education community who have contributed their time and expertise freely. And that’s a point I now want to ponder...

I was a member of the NZASE for twenty-two years, and during the past four years have been the Editor of the

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NZST. During my time as Editor I built upon the networks I developed during my teaching career – cajoling and pleading with colleagues to contribute to the NZST. I had no budget, just a strong belief in what you are all doing.

So, by sheer persistence and willpower, I have been able to bring you an insight into the NZ scientific community thereby enlivening your programmes. It’s now time to thank you all...

To all the many contributors over the past four years, I am indebted for your support. It was always a pleasure to work with you and to read your articles. Thank you.

I would like to personally acknowledge the support and encouragement given to me by Dr Dennis Gordon, of NIWA, who ensured that every issue of the NZST under my editorship featured an article from NIWA scientists. Thank you, Dennis.

I recall the first time I met John Campbell – at SciCon Christchurch 1990 – some of you may recall the fire walking, the laser light disco and John’s amazing lecture. John has contributed in many ways to the NZST under my editorship, most notably supplying ask-a-scientist. John, I am grateful for your generosity of spirit. Thank you.

I also met Rose Hipkins in the early 1990s, and she has been a stalwart of the NZST Editorial Board and I have valued her advice, insightfulness and support. Rose, thank you.

In December 2006, I wrote to Philip Catton inviting him to contribute an article on HPS, never imagining that he would be the most prodigious contributor under my editorship, writing on average 3500 words for every issue…no mean feat! His key motivating factor was to awaken your interest and understanding of this thing called science. Philip, we have both weathered storms this year, and you are right: this too shall pass. Thank you for your generosity of spirit and friendship.

Finally there is the team which ensures that the NZST is published to the highest standard. To my dear colleague Raymond Jones of K & M Print: I thank you, Raymond. It has been a joy to work with you during the past fourteen years. To my dear friend Philippa Proctor who typesets the NZST – Philippa your commitment to excellence and your willingness to meet the needs of contributors in a no-fuss way is legendary, my grateful thanks and aroha! And to my dear friend of old, Teresa Connor who proofreads the NZST – Teresa we have been on an amazing journey together, and it’s now time to begin a new one, with my heartfelt thanks and aroha!

To our loyal readers, it has been a privilege to be invited into your classrooms, and I hope in some small way we made a difference.

Kind regards,

Kia ora koutou, What an amazing treat at SciCon this year! There was a mixture of events that expanded our thinking about science and science education. Congratulations to the organising committee in Nelson for providing an extremely stimulating national science teachers’ Conference. Two of the Prime Minister’s prize winners presented highlights from their projects. Dr John Watt, as winner of the Emerging Scientist of the Year, discussed his fascinating work on nano-technology; and Paul Lowe, the winner of the Prime Minister’s Science Teacher Award, outlined his involvements with students in impressive number of problem-based learning projects.

The videos of his students flying gliders and diving to see underwater life were exciting examples of how to engage students directly in situational science contexts that they (and we) will never forget.

Throughout the Conference there were many other presentations and workshops that highlighted how individual passion, problem-solving approaches and science alongside technology can provide solutions for medical interventions, conservation and other ways to enhance the quality of life. For example, Dr Lisa-ann Gershwin effervesced passion in her keynote on the beauty, significance, deadliness and economic implications of jellyfish. Dr Mike Packer’s presentation on how algal growth may provide a source of future biofuels, and Serean Adams’ explanation of the requirements for successful cryopreservation, all provided examples of how scientists create solutions to important issues. Many other workshops provided specific emphases on how to teach specific content or enabled discussions about the multiple ways new (including digital) resources can be used. Many participants were guided through the science learning hub website: www.sciencelearn.org.nz as a drop in centre throughout the Conference. I would like to pass on the Association’s gratitude to all the sponsors of SciCon, because without them, there would not have been as many great activities or keynote presenters. The field trips on the last day of the Conference were also a huge success.

There is on-going debate around the content that should be included in science courses, how it is connected to everyday and applied uses of that knowledge, and therefore, what support and future directions are needed in terms of teaching and learning approaches. We are often dazzled by the promise of digital resources because they are very visual and engaging. However, it is also important to consider the teaching and learning approaches that support learning when using such resources.

There is no doubt that students need to develop specific knowledge and a range of skills while they are at school to prepare them for everyday decisions and actions, higher education and the kinds of activities they might be involved

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in when using science and technology in future careers. While we cannot predict what all of these will be, we can prepare students for activities that we know scientists do now. Collaboration, creatively designing experiments, finding ways to solve problems, and analysing and recording data are crucial activities in the scientific process. Many skills are transferrable across subject domains, for example: using Excel for recording data, setting up automatic calculations and generating graphs. While essay writing seems to be covered well in schools through a number of subject areas, science students (according to an engineering colleague) tend to arrive at university with little preparation in technical writing, particularly styles of writing needed for scientific reports. The experiences we provide students and the way assessment requirements are constructed, can make a huge difference to the knowledge and skills students obtain and retain. Working collaboratively is also a key part of how scientists work. This prompts the question: why do some assessments require students at senior levels to complete investigations by themselves?

Soon the Ministry of Education will be releasing the draft teaching and learning guidelines for science. This document emphasizes science as a process, which is a move away from science as a body of knowledge. The guidelines discuss how the Nature of Science can be integrated across the strands of science. The achievement objectives support an inquiry process that engages students in active exploration of what science is and how scientists work. It is also great to see an emphasis on the big ideas in science such as science is evidence-based; scientists use theories or models to describe the natural and physical world and science is influenced by society. The guidelines state that science is both logical and imaginative. Scientists discover, invent, adapt, combine, and apply ideas through inspiration, careful observation and critical thinking.

The teaching and learning guidelines for science will contain many ideas for developing and using indicators of students’ achievement, as well as comprehensive lists of possible activities across the achievement objectives for each level with assessment links. It is a document designed for teachers, to expand thinking about possible learning experiences and to connect science to students’ lives.

I strongly encourage you to send comments on these draft Teaching and Learning Guidelines to the Ministry of Education as part of the consultation process. It is very important to provide feedback so that teachers and students are well served by these supporting documents.

Noho ora mai Lindsey Conner President

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science and“Creative Destruction” Philip Catton, who co-ordinates the University of Canterbury programme in History and Philosophy of Science, at present is mid-flight within a series of NZST articles concerning what is “Western” about “Western science”. Here, however, he steps aside (terminally?) from this series to ask: is “goodbye” being said to NZST in its present form? More generally: with what willingness should humans send to the wall whole practices of theirs in which they previously saw impressive accomplishment? Or finally, in specific relation to science: does science vindicate the concept of “creative destruction”? Or does science teach the very opposite lesson?

“Creative destruction” and the phenomenology of pride Let us begin by considering ourselves. NZ, Inc. is, with each passing year, ever more heavily invested in the present-day, voguish concept of “creative destruction”. Am I profitable?

Am I economically efficient? NZ, Inc. asks of itself these questions and so do all its parts, and so also do the parts of those parts, and so on. A “no” to either question means the relevant part faces budget tightening. Even its key state services NZ, Inc. manages like businesses, making them accord with profit incentives. Unprofitable units at whatever level must either right themselves, or go to the wall.

Not everything that New Zealanders formerly valued did they value in dollars terms. (This includes many former great intellectual explorations, in science.) NZ’s switch everywhere to dollars-bottom-lines cannot possibly have conserved all former values. NZ, Inc. consequently sends to the wall many former goods that, economically, are difficult to make out as good.

Just as this shift is an affront to some old values, so also does it replace warm pride by cold pride. Pride is warm, that says: while NZ may be small, and at the end of the Earth, still what we accomplish here, together, is “not bad”.

Cold, is the haughty demand upon each and every unit that its “excellence” be professed. Warm is the understanding that good functioning is from mutual accomplishment, grounded in shared fortune, the good of which dollars can never remotely fully express. Cold pride receives the dollar as a given good, and as the only given good.

Warmly proud Kiwis have always thought self-maximising amiss. Good living as well as good functioning-for-others are, according to the warm view, dimensionally rich beyond reducibility to dollar incentives – as well as richly intertwined. Someone who is roundly fixed on selfishly construed dollar incentives is crass, and a bit of a loser, the warm Kiwi insists. NZ, Inc., however, starves the warmly proud of resources. To function is personally to profit, it says.

Excellence results from cold pride. The profitability of the whole stems from profitability in all the parts. The warmly proud are from the cold perspective worse than benighted: they are not playing the game. Selfishness is supposed by the cold to be unselfish, and conversely, unselfishness, selfish.

Warm and cold each see the other as perverse. As the change from warm to cold in New Zealand was beginning, warmly proud New Zealanders were told that they needed

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a “reality check”. How had anyone any right to be proud, with so little information capturable concerning what (in dollars) things truly cost? As the dollars-bottom-line reasoning took over, cold-proud New Zealanders have roundly altered speech. “Not bad” is over. They use the word “excellent” virtually in every sentence. Their units are “excellent”, they are “excellent”. Moreover, for them, all of that “excellence” not only requires for its possibility, but also must-needs be evidenced by, healthy dollarsbottom-lines.

The haughty pride about “excellence” demands, moreover, now – at least at high management echelons – that defeatism alone would speak the need for a “reality check”.“Not bad” was said to need a reality check. In the (management-as-religion) reverie of which managers of managers of managers of managers are capable, “excellence” functions as the only alternative to nullification. Consequently, concerning higher echelons, reality checks are over. Lower down, the market takes the hindmost, silently, while survivors-for-the-nonce redouble the chatter about, and trumpeting of, their own “excellence”.

Of course the hush of loss and the noisily boastful, hastened gallop of the new diminishes society’s ability to consider values reflectively, or thus to determine them wisely. For NZ, Inc., the market is the mechanism for determining what is good. Growth is from being profitable; profitability is the only good; so, the growth of the new is good. And if the growth of the new is at the expense of old things dwindling and disappearing, since dwindling is from not being profitable, and not being profitable is bad, the change, however destructive, is good. The very concept of “creative destruction” resonates with cold pride. Pride that is cold thinks: I am; therefore, I am excellent.

In sum, the concept of “creative destruction” encourages the conclusion that value is evanescent and impermanent, as though the only progress is the growth of the new, whatever the new might be, for example: HR; accountant clout; managers of managers of managers; whatever. The fittest survive. Might makes right. Justice is the interest of the strongest.

Hayek on Popper: does science vindicate the concept of “creative destruction”?

As the conservative economist F.A. Hayek helped to point out, the philosophy of science of Karl Popper can be construed in effect as endorsement of “creative destruction” and thus of cold pride. This interpretation of Popper, as it happens, fits very poorly the author himself. Popper was complicated; I would say he embodied, explosively, a mix of warm and cold each in epic proportions. Propelled (in 1937) to Christchurch by a darkening Europe, Popper toted to these parts a clarion pen and an incandescent passion against human irrationality. Popper wrote in Christchurch The Open Society and Its Enemies. Popper endorsed the idea that in an “open” society the fittest survive, but Popper meant by the relevant struggle only a struggle amongst ideas. So far as social arrangements are concerned, Popper was almost as cautious about change as Edmund Burke, and for similar reasons. To disturb the social pattern is always to disturb more than you intend to. While people might usefully

his appreciation for science by lauding in effect science’s cultivation of survival-of-the-fittest “creative destruction” among ideas. And far from accepting the point of view that in these circumstances reason dwindles, Popper proposed to understand reason itself, in effect, in terms of such (ideas-based) “creative destruction”. Popper called his philosophy “critical rationalism”. Popper’s philosophy in effect reminded Hayek of economic rationalism.

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Defects of “critical rationalism” Popper estimates to be scientists only persons who possess proper humility before reason. Scientists are, in Popper’s estimation, ever willing to criticise any of the convictions that they possess. They seek to explain, but they acknowledge the likelihood that they have as yet failed in this task. Scientists are worthy because they practise unworthiness. They stand not as authorities. They possess instead the mode of knowing-that-they-do-notknow. It is in this way only that reason shines forth from them. At any rate, all this is what Popper insists is needed if a person should truly count as a scientist.

In many earlier NZST articles of mine, I have considered the evidence as I see it against Popper’s “critical rationalism” as explanation for how science works. Partly, I explored reasons to favour, over Popper’s view that science in its every part seeks theories that adequately predict what we observe, the view instead that science across its many parts seeks theories that harmonise phenomena.

I explained how far different such harmonising is from merely predicting, as well as how far phenomena are different from what we merely observe, and I explained the similarity between these differences. Key to determining what phenomena there are, I argued, are acts of measurement. I discussed the poverty of Popper’s “critical rationalist” standpoint for fathoming the form and power of measurement in science. By a measurement, science secures no mere test of its theories. Every measurement ingeniously enables science, by partly practical means, to deduce something theoretical, from a well-chosen empirical fact. A measured understanding is one that is over-determined by measurement, that is, is determined in this way by measurement from many sides. In that, is harmony. Therefore, in science, harmony is perfectly key. Harmony much binds the parts of science together, conferring synthetic wholeness upon science.

I also compared Popper’s view with the far different, more sociologically-oriented understanding of science of Thomas Kuhn. Popper was himself alert to some ways in which science is not merely what a scientist does, times the number of scientists that there are. But Kuhn is more forceful in pulling our attention up to the level of the collective, in order to understand the operation of science at this level. Like the theory of moral development according to Aristotle, Kuhn teaches how new experts are made only when there are already-extant experts to emulate. Kuhn wrongly construes exemplary expertise narrowly as “puzzle-solving”, when in fact the creative, open-textured performance of ingenious, telling measurements is key. Yet measurement-making could come to nothing without established expertise. So, while Kuhn misconstrues and inadequately appreciates measurement, and so wrongly concludes that expert-led science will for the longest while be closed to substantial theory revision, still, even if in fact expert-led science is typically open not closed, it carries a form that Popper, who opposes the very idea of “experts” since he treats all knowledge as tentative, cannot fathom very well.

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question existing social arrangements, they should ever be cautious about change; careful piecemeal tinkering alone is called for, in a spirit not revolutionary, but rather ever alert to missteps. Yet in Popper’s view, the order that is to be maintained more or less wholesale, with only piecemeal, experimental change, flourishes only to the extent that it remains intellectually ‘open’, and thus able, in whatever way, to sustain critical debate about ideas.

The New Zealand of Popper’s day was a welfare state, and Popper lauded it as the most corruption-free, maximally “open” society he had ever experienced. A socialist in his youth, roughly concurrently with the Russian Revolution, Popper had become alarmed, it is true, by the revolutionary fervour of socialism. He correctly anticipated that revolutionary changes, however socialist, would, wherever they happened, in fact destroy intellectual openness. He admired greatly the way in which significant socialism had arrived to New Zealand, democratically.

By the same caution in him about revolutionary change, Popper would have been appalled about New Zealand’s rapid recent change into NZ, Inc. To take one illustration, the pace of change in the NZ school system would have seemed to him absolute folly: you can’t change everything all at once and in the least way note the missteps or thus learn from your mistakes. NZ has not husbanded what was working, and its pace of change far exceeds that of responsible “tinkering” in Popper’s sense of that word.

Moreover, the same concern in Popper, that socialist revolutionary change would destroy intellectual openness, applies well to the “economic rationalism” of NZ, Inc. Intellectually how open is a society so far addicted as NZ, Inc. is, to the rhetoric of “excellence”? In NZ, Inc., naysayers to this rhetoric will likely be nullified. In consequence, the chatter about “excellence” in fact registers fear. Fear that what is working might shortly succumb under the grinding pace of change, or fear simply for one’s job, ever promotes the rhetoric of “excellence” in NZ, Inc. Notably the rhetoric checks measuredness, and so actually helps accelerate the pace of change. Fear is the emotion that readies human beings for rapid change in what they are willing to do. By contrast, courageous persons, in situations where courage is called for, may rapidly change what they do, but they would not then and there change what they are willing to do. What courageous persons are willing to do comes from a steadier, more measured, conviction.

Because speech is action, and action (especially in fearful times) may result in social costs to us, courage is much called for in relation to ideas. For example, it can often be courageous to declare that might is not necessarily right, or that justice is not the interest of the strongest. Fearlessly to declare that the presently mighty are actually not right, or that justice would check the strongest rather than merely serve them, proceeds always from persons of courage. The willingness to declare such things inevitably reflects in the agent steady, measured, conviction. A case in point in fact is Popper’s own, very clarion, in these dimensions warm, Open Society book.

Still, however wayward it is in fact, Hayek’s understanding of Popper can readily be seen to have its point. Science has parts, and the parts have parts, and those have parts too, and so on. Popper does say that the unique strength of science is its willingness, at every level, to allow what no longer works to go to the wall. (Nevertheless Popper meant that in science not practitioners, but no longer working ideas should go to the wall.) Popper truly did frame

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Ironically there is a way to chart a path from Popper towards fairly substantial agreement with what Kuhn should have said. This would mobilise Popper’s own Burkean caution about social change. In particular, we need in that way to allow a “critical rationalist” to refuse wantonly to send to the wall whole practices, in science, in which people previously saw impressive accomplishment.

To follow this path, Popper needs to compromise his own emphasis on tentativity of conviction, by acknowledging the settled, measured conviction that there can be that presumed expertise is laudable, or thus that experts’ practices possess true worth. The philosophy of science, not only the social philosophy, of Popper, needs to build in recognition of warrant, from settled, measured conviction.

Unfortunately it was a struggle for Popper to do this well; some considerable steps of his in this direction faltered in the end upon the key issue of his anti-inductivism. (But in earlier NZST articles I have also argued that Popper’s extreme official anti-inductivism is the very signature of a mistake.)

Looking to science, then, we are not shown worth in the concept of “creative destruction”. On the contrary, we see significant reasons, after all, not to send to the wall whole practices in which people previously saw impressive accomplishment. Popper’s own advice merely to tinker with extant arrangements, so that in making such piecemeal change, one can be ever careful to watch for missteps, stands warmly opposed to the cold concept of “creative destruction”.

Replace Popper’s hypothetico-deductivist philosophy of science by one duly invested in synthetic interest in harmony, moreover, and lessons from science against lauding “creative destruction” come through even more clearly. Whereas the concept of “creative destruction” encourages the conclusion that value is evanescent and impermanent, as though the only progress is the growth of the new, whatever the new might be, synthetic philosophical rumination concerning creativity counters this completely. We are in its spirit liable to link true creativity with courageousness, i.e. with acts that even as they issue in something new are comprehending of prior reasons for why this new is good. Absent will be any inclination to celebrate the new whatever the new is.

(Popper was too complicated in himself quite successfully to make this out. His philosophy encourages boldness.

Boldness is but the outer shell of courage. It misses the current points.)

True creativity, far from destroying what it replaces, corrects what has gone before constructively; it enhances much stable, measured rightness in what has gone before.

Thus in science, by creative intellectual advance, former understandings are significantly tweaked it is true, and yet are so by dint of being deepened. In such advances, former estimations of what is valuable are roundly, if also correctively, vindicated. Thus we can consider Galileo as winning into view some enduringly valuable insights about projectile motion, just as Kepler won into view some enduringly valuable insights about orbital motions.

It is true that the very facts themselves that were embraced in the thinking of each historical figure were received anew in altered forms by Newton as a result of his courageous, creative accomplishment. To comprehend as Newton did in rationally harmonious ways what had seemed disparate formerly – the flight of a projectile, the orbital path of a planet – Newton had to correct each of his predecessors significantly. But he also roundly attested to their worth. By showing us the limits, he also more fully revealed the scope, of the very fine insight into things

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that each of his predecessors had possessed. I believe that bringing harmony to situations is always thus creative; matters can never be made more consilient without at the same time being subtly and pervasively shifted in their character.

I wish that our minds in the present day could be focused the more on such ambitions, for creativity through harmonisation. I doubt whether creativity truly admits of any other kind. (Our present need is not for the boldness that abounds, but instead, for clear-headed, considered, courage.)

Worries about New Zealand Science The pages of NZST have ever richly purveyed enticing studies of worthy science being done in New Zealand, themed always around aspects of the school science curriculum. I will miss very much these studies, if the NZST disappears [in its current form]. At the same time, the threat of that disappearance couples in rounder respects to concerns I have for New Zealand science. What NZ, Inc. shapes New Zealand science to be, is a concern to me.

Bear in mind how significantly the New Zealand science establishment grew during the 1950s, 1960s and 1970s.

In those decades the science establishment mostly comprised public science, unshackled by the public purse from private money interests. Like other parties to the Cold War, New Zealand sent public money into science with few but military, health and agricultural strings attached. This was the capitalist West’s way to demonstrate its superiority to the system on the far side of the Iron Curtain. Meanwhile Communist nations, with the like goal of demonstrating superiority, likewise sent public money into science with few but military, health and agricultural strings attached. Support for pure science was a way to show off. In the West, including New Zealand, even before the Cold War ended however, money was much speaking against curiosity-driven science, and much instead shackling science to profits. And by the present day, well into post-Cold War conditions, the showing-off is altogether abated, so that science in New Zealand, and elsewhere, is profoundly shaped either by corporate interests or by government estimations of how the economy best can grow.

New Zealand science has evolved palpably altered institutional forms at an extraordinarily rapid clip. A notable feature is how significantly New Zealand scientists compete with one another for funding, even to protect their very jobs. The funding is moreover very significantly tied to applied goals. The goals ever more assuredly cannot be to increase understanding-of-the-world of kinds that might ground caution about economic activities. Whistle-blowing expertise is not cultivated. The skills of scientists are ever more squarely settled into immediate positive connection with profits.

These changes are degrading of the science as science.

For, the new competition-based institutional form for science in New Zealand fractures good social relations among scientists. Moreover, it sends the research done into fractured relation to a million focused needs of agriculture or industry. Yet as an intellectual effort, science flourishes the more, the more it grows harmony. For example, the courage of Newton, without what was gathered into it from others, simply could never have been.

The present NZ, Inc. model for the scientific activity could not be more deeply wedded than it is to the false conception that science is what a scientist does, times the number of scientists that there are. NZ, Inc. pulls scientists apart from one another, and destroys the

Why educators know, warmly, what is key The cold understanding that “I am, therefore I am excellent” recapitulates more than somewhat the mistaken Cartesian philosophical starting-point: “I think, therefore I am”, though it is far worse perverted. “I am, because I think” in fact is a poor place for philosophy to start. Philosophy of science has helped to show why. The problem with Descartes’ starting point is especially evident in science. Especially if you are a scientist, you in fact are to your fellows much as your shadow is to you. You depend upon them for your very being. You cannot coherently want all the light to fall on you, not even – indeed, most especially not – in order for you to inquire well after what you are. For unless light falls onto your fellows, you would not even be. All intellection, including concerning ‘what am I?’, is originally and ineluctably social.

Educators are reflexively aware of all this. For consider from educators’ standpoint what the self is. Selfhood is not from this standpoint but a biological fact, an origination of egg and sperm conception, or even of long biological gestation. Selfhood is from this standpoint clearly social.

How is it accomplished? Even as the babe inhales its first breath, its fellows stand ready to exclaim a difference to the world that this new one makes. Without yet a moment’s assimilation to its society and not a concept in its head, still the baby’s fellows seek to recognise that it does things.

The freshness from this is received as a wonder. All going well, that wonder will endure, and energise years of effort, to cultivate, following this mere birth, a new, ever more robustly emerged, self.

In order for concepts to form, the babe must be brought into behavioural conformity with its fellows. Its motor co-ordination must become ever better recognisable

as “actions” by its society. Speech will come, and will far enhance the process; for, its acquiring conformity with fellows, say in the discrimination of when to say “red” from when not to say that, just is the laying down of a concept. (New experts are made only when there are already-extant experts to emulate.) Yet all the while that society works up conformity, and so concepts, in the child, also it works to cultivate the child’s power not to conform.

Agency as owned by the child is recognised from the first moment, perhaps fancifully – but with the enormous purpose, of socially creating a self. As years go by, oft will be the occasions of exaggerated attribution of agency, and oft at the same time will be reticence, from kindness, to attribute agency at all. The same child that is credited with a brilliant crayon stroke will be not held truly responsible for, say, a tantrum at bedtime. The latter is a stage, the former is an accomplishment. In this way society creates a seat of agency and nurtures it to strength, and so eventually realises a new self.

NZ, Inc., and competitive science, both forget how fully we are all together in this life. Society is not what each person does times the number of people that there are.

For there is a beautiful priority, of society to each self.

Science also, is not what scientists do, times the number of scientists. Science deeply depends upon harmony, and thus upon the collective, not merely upon individuals. The reduction of neither society, nor science, to mere multitudes, truly works. Happily, in just the way these reductions are unstable, eventually the reign of managers of managers of managers will be seen to make no sense.

NZ, Inc. is not fated to last forever; its terror will pass.

For further information contact: philip.catton@canterbury.ac.nz During the past four years, Philip has taken readers on an amazing journey into the nature of science itself: its history and philosophy. His generosity of spirit has been much appreciated – Ed.

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How did Rutherford go about splitting the atom?

Hannah Bos, of Waimea College John Campbell, a physicist at the University of Canterbury and the author of “Rutherford Scientist Supreme” and www. rutherford.org.nz, responded.

Behind many great discoveries is a long history of hard work.

By 1907, Rutherford in Canada was firing alpha particles (i.e. the nuclei of helium atoms) at gases and thin solids, and showing that some alpha particles were scattered, i.e. the beam became fuzzy.

After he moved to Manchester in 1907, he had his assistant, Hans Geiger, study this scattering. An undergraduate student, Ernest Marsden, who later came to New Zealand to work, was asked to see if he could detect any alpha particles which had been scattered through very large angles. He discovered that some were scattered backwards. In 1911, Rutherford interpreted these results as showing that the nucleus of an atom was very tiny, about a thousandth the diameter of an atom.

Rutherford then had Marsden play marbles with atoms. He fired alpha particles at materials which were made up of

light atoms, e.g. wax as it has lots of light hydrogen atoms in it. When an alpha particle hit a hydrogen nucleus head on, the light hydrogen nucleus was sent flying, much like a large marble hitting a small one.

Because the nucleus is so small only about one in every ten thousand alpha particles struck a hydrogen nucleus headon.

In 1917, late in the First World War, Rutherford was sufficiently free of war work to be able to go back to these experiments. He fired alpha particles at different gases.

With nitrogen gas he found hydrogen nuclei being ejected with energies that were far higher than the energy of the incoming alpha particle. So these weren’t nuclei from hydrogen atoms but a hydrogen nucleus from inside the nitrogen nucleus. He had split the nucleus. That nuclear reaction is shown on the 1971 New Zealand 7c postal stamp.

In inducing this nuclear reaction, Rutherford was not only the first person to split the atom, but also the world’s first successful alchemist.

For further information contact: questions@ask-a-scientist.net

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possibility for courage. Like so many others, NZ scientists are much fearful for their jobs, and keen to be “excellent” in whatever way the forms for their further funding demands from them.

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AllanWilson and testing the Out of Africa model for human origins Allan Wilson, a kid from Pukekohe, helped our understanding of our human origins as Professor David Penny, Massey University, explains: Introduction Allan Wilson (Figure 1) was a New Zealander who revolutionized the study of human origins, and whose lab proposed the Out of Africa hypothesis for the origins of modern humans. Allan grew up on a dairy farm in Pukekohe, attended King’s College in Auckland, did an undergraduate degree in Zoology at Otago, and then left for his graduate work in North America. He did a masterate and then a PhD in Biochemistry, spent a postdoctoral period in Boston, and then spent many years as a member of the faculty in the Biochemistry Department in the University of California in Berkeley (just across the Bay from San Francisco). His knowledge of both classical biology (from his zoology undergraduate degree) and of biochemistry was a major advantage when studying human origins.

Beginning to understand our human origins Charles Darwin (following the conclusions of Thomas Huxley, a famous mid-19th century anatomist) inferred that humans had evolved in Africa. Based on anatomy, Huxley had found that chimpanzees and gorillas were the closest

relatives of humans, and because these other two species are African, then the simplest explanation was that humans arose there also. This is a common reasoning in biology, and is simply that the ‘centre of diversity’ of a group is also its centre of origin. Yes, it is the simplest explanation, but we could all think of other more complicated explanations, but until we get more evidence we use the simplest.

However, an African origin for humans was not generally accepted in the first half of the 20th century – possibly for non-scientific reasons, such as wanting Europe (or possibly Asia) to be the homeland of all humans. Bowler (1984) reports on some early aspects of evolutionary ideas.

Well really, there was no additional evidence in the first half of the 20th century, and a theme I will use repeatedly is that for a hypothesis to be ‘useful’ it has to lead to predictions that can be tested. And the more specific the prediction the more useful the hypothesis, the easier it is to test. So in this sense I am following the philosophy of science propounded by Karl Popper, a well-known philosopher of science who also has New Zealand connections. Although born in Austria, he spent several years at the University of Canterbury in Christchurch before moving to the University of London (see his autobiography, Popper 1976). Yes, sometimes predictions may take a while for new techniques to be developed, but we all like it when predictions can be tested – that is real science.

Origin of modern humans

Figure 1: Allan Charles Wilson (1934–1991), the Kiwi who solved human origins and dispersal – one of the last photographs, circulated at his funeral in 1991. See also http://en.wikipedia.org/wiki/Allan_Wilson.

New Zealand Association of Science Educators

To return to Allan Wilson, a real strength was his ability to apply the developing techniques of molecular biology to the fundamental questions from classical biology. Although Wilson studied many aspects of molecular evolution, we will only consider here the human origins. We see him starting off by comparing the strengths of immunological reaction between equivalent proteins from different species, then moving to some general features of DNA sequence (such as how frequently a particular sub-sequence occurred that was recognized by a specific enzyme), and finally to DNA sequences themselves.

Oops... but first we should explain the two models/ hypotheses that we are comparing and so introduce some background. When I was still a graduate student, Louis Leakey made a tour of North America, giving lectures about his new human fossil discoveries in East Africa. At a reception afterwards, some palaeontologists were not impressed – he is looking in the wrong place, they said, “we all know” that humans evolved in Asia.

In contrast, some molecular biologists were very impressed by the Leakey fossils. “Look” they said, “Morris Goodman [in Detroit] is showing by immunology that humans, chimpanzees and gorillas are all very closely related”. So, because these other two species are African, we should be looking in Africa for the earliest human fossils, and this guy is looking in Africa and, yes, he is finding very early human fossils (as predicted by the results of Morris Goodman).

The Leakey fossils were very quickly accepted, and Africa became the place to look for the earliest human fossils; and we now have many African fossils over the last 5 million years (Myr). So we see a ‘consilience of induction’ (to use an old phrase) with similar conclusions coming from both

Out of Africa Hypothesis The Out of Africa hypothesis is that modern humans evolved in Africa, and that a subset of them later moved ‘Out of Africa’ into Asia and Europe, and eventually to the rest of the world. On this model, genetic diversity is predicted to be highest in Africa, and lesser elsewhere. Although we will see that much of the work was reported earlier, the model is often considered as dating from 1992 (Wilson and Cann, 1992), though some of the information was available many years earlier. The model also envisages that earlier forms of Homo that migrated into Asia and Europe did not evolve into modern humans, even though (as closely related ‘species’) there could have been some interbreeding (what geneticists will call introgression). In other words, basically these early fossils from Asia and Europe have no direct descendants.

However, do be careful here, the phrase ‘Out of Africa’ can in principle also be used to describe the very earliest Homo movement from Africa into Asia and Europe, or to the Neanderthals, or to other intermediate groups. When we refer to the “Out of Africa’ model, as contrasted to the ’multiregional model’, we are referring to the origin of modern humans. So the multiregional model is next.

Multiregional Model In contrast, the Multiregional model (see Thorne and Wolpoff 1992) suggests that these early humans (in Africa, Europe and Asia) all gradually evolved into modern humans. So if humans were a very old population that had existed for more than a million years in each of Europe, Asia and Africa, then basic population genetics tells us there would be extremely high genetic diversity both with and between the populations. You would also expect that if the populations had existed in the three regions for over a million years, there would also be some very old genetic diversity limited to each of the continents. So not only would the overall genetic diversity be very high, there was also be some very deeply diverged (and unique) alleles in each population (an allele is a particular sequence of a gene). Okay, you could also think up some alternatives to Out of Africa and multiregionalism; what about a hypothesis that early humans in Asia evolved into modern humans, and then spread to the rest of the world, displacing the earlier inhabitants in Europe and Africa. You could also think about testing these other models, though we will concentrate on the two main models.

So what I aim to do here is to look at how some of the research has given us new information over the last half-century, particularly in relation to the Out of Africa and the Multiregional models. I will particularly focus on how models/hypotheses can be used to generate tests to evaluate the ideas. Good science must always avoid just accepting models without testing them. The two main models referred to here have certainly led to a lot of testing, and we can see major progress over the last few decades.

The Allan Wilson Lab informs models As mentioned earlier, the research of the Allan Wilson Lab on comparative human genetics started quite early, and we will start with Sarich and Wilson (1967). The abstract from this paper states, “Several workers have observed that there is an extremely close immunological resemblance between the serum albumins

of apes and man. Our studies with the quantitative microcomplement fixation method confirm this observation. To explain the closeness of the resemblance, previous workers suggested that there has been a slowing down of albumin evolution since the time of divergence of apes and man. Recent evidence, however, indicates that the albumin molecule has evolved at a steady rate. Hence, we suggest that apes and man have a more recent common ancestry than is usually supposed. Our calculations lead to the suggestion that, if man and Old World monkeys last shared a common ancestor 30 million years ago, then man and African apes shared a common ancestor 5 million years ago ...”.

Note that this early work was measuring the strength of the immunological cross-reactions between the same functional protein from different species. In this 1967 paper they could not tell the order of divergences of chimps, gorillas and humans, and left it as a three-way split (a ‘trichotomy’). Later work showed gorillas separated first, and then chimps and humans split (maybe a million years later). The main point here is that humans are not a very ancient lineage from 20–30 million years ago (Mya). Maybe it is pushing it a bit, but I think we can say: Out of Africa 1, Multiregional hypotheses 0.

Perhaps that is an honorary point, but we now have a start and geologically-speaking, humans are not a very ancient lineage (though 5–6 Mya is still pretty old, but certainly it is not 30 Mya. The second paper from the Wilson Lab that is relevant here is over a decade later, and reported that humans had low genetic diversity (the following abstract is from Ferris et al.

1981).

“Ape species are 2-10 times more variable than the human species with respect to the nucleotide sequence of mtDNA, even though ape populations have been smaller than the human population for at least 10,000 years…The amount of intraspecific sequence divergence was greatest between orangutans of Borneo and Sumatra…The least amount of sequence variation [for apes] occurred among lowland gorillas, which exhibit only twice as much sequence variation as humans. The large intraspecific differences among apes, together with the geological and protein evidence, leads us to propose that each ape species is the remnant of an ancient and widespread population that became subdivided geographically and reduced in size and range, perhaps by hominid competition.”

That low genetic diversity among humans is pretty striking! The lineage to modern humans does not seem to have been in Africa and in Asia and in Europe for several million years – or else they would have very high genetic diversity. At that time the explanation was based more on a reduction in size of ape populations; these days we would focus on the rapid increase in human numbers over the last 100,000 years or so. So we can add this support from the low genetic diversity to the Out of Africa model, and get: Out of Africa 2, Multiregional hypotheses 0.

The formal description of the multiregional model is often taken as the Scientific American article of Thorne and Wolpoff (1992). But you will see that the Ferris paper was a decade earlier, it was already known that humans had a low genetic diversity. So in a sense, this point to Out of Africa is almost an ‘own goal’ from the multiregional model.

But we had better be careful here; these results contradict the multiregional model of a large population size over millions of years, but do not yet focus specifically on Africa. If this was all the information we had, we could not distinguish a founding human population in Asia, in Africa, or in Europe. (Humans only got to Australia about 50,000

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paleontology and molecular biology – good science.

Thus it was soon accepted that Africa was the ultimate homeland of humans. But it was also found that later human fossils (Homo, but not H. sapiens) from between 1.5 and 2 million years ago (Mya) were also found in both Europe and Asia. So we can have at least two models.

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Box 1 A representation of the low genetic diversity in humans, and the increasing diversity in gorillas, chimpanzees, and orang-utans. (See Box 2 for how this could be measured).

years ago, and to the Americas a bit over 11,000 years ago, so we can leave both those Continents out for now.)

The next piece of evidence, also from Allan Wilson’s Lab, was from the PhD thesis of Rebecca Cann, published as Cann et al. (1987). She used the newly available techniques to measure more directly some of the genetic diversity in mitochondrial DNA within and between human populations from around the world. Her results did include many people from Africa, Asia and Europe so could focus on each Continent in turn. It was from this paper that the Out of Africa phrase was coined, and also ‘mitochondrial Eve’ (Becky Cann became known as ‘mother of Eve’, and Allan Wilson, because the work was done in his lab, was sometimes called ‘father of Eve’. But be very careful here – talking of ‘Eve’ does NOT, NOT, NOT imply there was only one woman in the community! Indeed, other estimates are around 5–10 thousand women (and presumably a similar number of males!). But just by chance, and given a long time, only one version will persist. For example, a women may have three sons reaching adulthood, but her mitochondria will not have been passed on. (The length of mitochondrial DNA is only about one part in 100,000 of your total nuclear DNA, but it is maternally inherited – both sons and daughters get it from their mothers). Anyway: Out of Africa 3, Multiregional hypotheses 0.

The work of Becky Cann used special enzymes that recognised just short sequences of DNA, and so was an indirect measure of DNA sequence diversity. The next test came after DNA sequencing became available, and even though it was initially difficult (and only a few hundred bases/nucleotides could be sequenced) it was a more direct approach – allowing a more quantitative testing of hypotheses. So DNA sequences from many humans were then published from Allan Wilson’s Lab, namely Vigilant et al. (1991). This showed even more strongly the higher genetic diversity in Africa, and lower diversity outside Africa.

So this was another test of the two hypotheses, and so we now have: Out of Africa 4, Multiregional hypotheses 0.

So the Out of Africa model has passed four tests, but although everyone has mitochondrial DNA in their cells, it is only inherited from mothers. So perhaps we should be 10 New Zealand Association of Science Educators

careful and say all the mothers came out of Africa; but what about the fathers? Given the slower rate of geographic dispersal in the distant past, it is not expected that the males would be different. But let’s check the Y-chromosome that is only found in males. Although it is unlikely, maybe the males could have come from somewhere else (no, not Mars)—we should check. This took somewhat longer because nuclear DNA is slower evolving than mitochondrial DNA, and techniques had to improve in order to get longer DNA sequences. However, when Ke et al (2001) did study 12,000 Y-chromosomes from around the world they found that they also had their highest diversity in Africa. So the Out of Africa model has passed another test: Out of Africa 5, Multiregional hypotheses 0.

So we now have all the mothers and all the fathers coming ‘Out of Africa’, isn’t that enough? But some people just can’t stop testing ideas even more thoroughly. What about all the other autosomal genes – those in the nucleus but not on the sex-chromosomes; that is, not on the X and Y chromosomes. That required even more improvements in techniques, but they have now been sequenced and analysed (see Sarah Tishkoff et al. 2009). Again we find the highest diversity within Africa, so: Out of Africa 6, Multiregional hypotheses 0.

But you can’t stop some people. Another test was to sequence the whole mitochondrial genome (c. 17,000 nucleotides) from Neanderthals. On the multiregional model, this should be within the diversity of modern humans (because of the suggestion that Neanderthals gradually evolved into modern humans – perhaps with some admixture of genes from other populations). But no, the Neanderthal mitochondrial genomes were well outside the diversity of modern humans, including those of modern Europeans. The reference given here is to a group of five Neanderthal mitochondrial genomes (Briggs et al. 2009), because that allows a comparison with the full diversity of Neanderthals; giving an even stronger conclusion. So now we have: Out of Africa 7, Multiregional hypotheses 0.

Surely that is enough, but the latest advance is from 2010 – the publication of the full Neanderthal genome (Green et al 2010). Again, that shows that the nuclear DNA of

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Neanderthals is outside that of modern humans: Out of Africa 8, Multiregional hypotheses 0.

It is useful to note here that most work on Neanderthal genomes is done in Leipzig (Germany) in the lab of Svante Paabo. He developed the initial techniques for ancient DNA while working as a postdoctoral fellow in Berkeley in Allan Wilson’s Lab. So there is another link there, and science is truly international. As an aside perhaps, the Leipzig group is very keen on finding evidence for any interbreeding between Neanderthals and early modern Europeans. Geneticists often call this ‘introgression’, where by interbreeding some genes pass between related ‘subspecies’. Maybe there is 2–3% introgression of Neanderthal genes into modern humans, but there is nothing in any introgression that makes us distinctly human – the fossil evidence is that modern humans are identifiable in Africa 50–100,000 years before they arrive in Asia and Europe.

So that is about it really. The Out of Africa hypothesis for origin of modern humans makes testable predictions, and these predictions keep passing new and more specific tests.

In contrast, the Multiregional model keeps failing test after test after test. So should we consider the Out of Africa the Gryffindor model, and the Multiregional model the Slytherin one! But no, we should never be too judgemental.

You can hear scientists say that ‘xxx was a good hypothesis; yes, we have proved it wrong, but it led to us devising several new tests in order to do so’. That is a much more positive approach – never ‘believe’ your models, but use them to devise more and more specific tests. So remember, “belief is the curse of the thinking class”.

Conclusion What lessons should we learn from all this? The one I will comment on here is that we need both specialisation and generalisation in science. Yes, we need specialists in different areas, but we always need to be aware of good data from outside our area of specialisation. New Zealand is fortunate that we have good communication between geologists/palaeontologists and molecular evolution/ systematics’ researchers. Over the last decade or so here we have had four one-day conferences on ‘Geology and Genes’ when both groups of researchers have met and compared

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For mitochondrial DNA, the highest diversity is found in Africa, and only a subset of the diversity (in the group L3) is found outside Africa (though many L3 sequences also occur within Africa).

The central part of the figure shows the oldest sequences and the further out from the centre the more mutations that have occurred. This from a study (Watson and Penny 2003) that found that the Turkana people of Kenya (East Africa) have the highest genetic diversity in the world for their mitochondrial DNA, and they live in the region where some of the earliest human fossils are found. Presumably modern humans have lived in that general region longer than anywhere else in the world. The top-right insert shows the number of difference between any two sequences.

their results, their questions, and look for new possible collaborations. The latest, was in Christchurch in 2009, and abstracts are available at: http://tinyurl.com/2be753s. There certainly is a moral here: good communication between different areas of science is extremely important, even if most of the time we work in our own specialities.

So the kid from Pukekohe really did help change the world.

By having a good background in classical zoology, and in biochemistry/genetics, and by introducing new methods of laboratory analysis, he really helped understand our human origins from Africa to the rest of the world.

For further information contact: d.penny@massey.ac.nz

Acknowledgments This paper was presented and discussed at an Allan Wilson Centre Teachers’ Workshop held in Palmerston North in 2010. Further material from this Workshop can be found at www.allanwilsoncentre.ac.nz

References (Most articles are available from the Allan Wilson Centre Website).

Bowler, P.J. (1984). Evolution: The history of an idea. University of California Press, Los Angeles.

Briggs, A.W. & 17 others (2009). Targeted retrieval and analysis of five Neanderthal mtDNA genomes. Science, 325, 318-321.

Cann, R.L., Stoneking, M., & Wilson, A.C. (1987). Mitochondrial-DNA and human evolution. Nature, 325, 31-36.

Ferris, S.D., Brown, W.M., Davidson, W.S., & Wilson, A.C. (1981). Extensive polymorphism in the mitochondrial DNA of apes. Proc Natl Acad. Sci. USA, 78, 6319-6323.

Green, R.E., & 55 other authors. (2010). A draft sequence of the Neanderthal genome. Science, 328, 710-722 Ke, Y.H., & 22 other authors (2001). African origin of modern humans in East Asia: A tale of 12,000 Y chromosomes. Science, 292, 1151-1153.

Krause, J., & 6 others (2010). The complete mitochondrial DNA genome of an unknown hominin from southern Siberia. Nature, 464, 894-897.

Popper, K.R. (1976). Unended Quest: an intellectual autobiography. Fontana.

Sarich, V., & Wilson, A. (1967). Immunological time scale for hominid evolution.

Science, 158, 1200-1203.

Thorne, A.G., & Wolpoff, M.H. (1992). The multiregional evolution of humans.

Scientific American, 266(4), 28-33.

Tishkoff, S.A., et al. (2009). The genetic structure and history of Africans and African Americans. Science, 324, 1035-1044.

Vigilant, L., Stoneking, M., Harpending, H., Hawkes, K., & Wilson, A.C., (1991). African populations and the evolution of human mitochondrial DNA. Science, 253, 1503-1507.

Watson, E.E., & Penny, D. (2003). DNA and people: From East Africa to Aotearoa New Zealand. New Zealand Science Review, 60, 29-35.

Wilson, A.C., & Cann, R.L. (1992). The recent African genesis of humans. Scientific American, 266(4), 22-27.

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new! ANZCCART resource

New science resource promotes informed discussion of care of animals in research A new science resource has been developed by the New Zealand Board of the Australian and New Zealand Council for the Care of Animals in Research and Teaching (ANZCCART) for Years 9 and 10 students. Its aim is to promote informed discussion about the care of animals in research. It consists of a DVD featuring prominent New Zealand scientists talking about their research, and a CD of resources based on the interviews. Two copies of the resource have been provided free to each secondary school.

The centrepiece of the resource is the DVD which features a wide range of socio-scientific issues that are relevant in

today’s world. Dr Jessie Jacobson, the 2007 MacDiarmid Young Scientist of the Year, narrates an overview of the seven interviews and talks about reasons why animals are used in research.

Each of the interviews is accompanied by a series of lessons.

Each series has relevant Achievement Objectives with a focus on the new overarching strand, The Nature of Science in the school science curriculum.

For further information, contact: anzccart@royalsociety.org.nz

ask-a-scientistcreatedbyDr.JohnCampbell How does an aqualung work?

Rowan Hayes, King’s High School John Campbell, a physicist who has been diving for nearly half a century, responded.

Ah, your question takes me back to the old days. One great advance in diving equipment was the invention of air pumps which could keep an open-bottom diving bell full of fresh air. I trained in a modern version of this, the old copper helmet standard diving dress. If the pump or pipes on the surface failed so that the air pressure in the helmet fell to surface pressure, then the diver would be compressed into the helmet by the surrounding water pressure.

Sports’ divers use compressed air because oxygen is poisonous at pressures greater than two times atmospheric pressure. The main advance in self-contained underwater breathing apparatus (SCUBA) was the 1815 invention of two Frenchmen, Beniot Rouquayol a mining engineer, and Auguste Denayrouze a navy officer. They used a membrane subjected to the surrounding water pressure to regulate a valve which allowed air to flow to the lungs only while a diver was breathing in, hence the term demand valve.

This invention was forgotten until 1942 when again two Frenchmen, Emile Gagnan an engineer, and Jacques-Yves Cousteau a navy officer and keen skin diver, applied it to make true scuba equipment.

Nowadays, aqualungs are two-stage devices. The second stage, at the end of the hose by the mouth, uses a modern version of the Rouquayol-Denayrouze valve. That way, the diver gets air at the same pressure as the surrounding water.

Modern diving cylinders contain air compressed to about 200 times atmospheric pressure. To make control easy, the air in the hose is maintained at an intermediate pressure of about eight times atmospheric pressure. A spring-loaded valve where the hose is attached to the tank (the first stage) lets air flow from the tank into the hose only when the air pressure in the hose falls, i.e. when the second stage opens as the diver breathes in.

Thirty years ago, I saw a film of mice using their own water-filled lungs to breathe under highly oxygenated water. Shades of the Kevin Costner character in the film “Waterworld”.

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Where did air come from?

Timothy Chisholm, Kaikorai Primary School Murray McEwan, a chemist at the University of Canterbury who works with NASA on planetary atmospheres, responded.

Air is the “stuff” that makes up the Earth’s atmosphere.

Our Earth is just one of the planets that make up our Solar System of Sun and planets and most, but not all, of these planets have atmospheres. Earth is special because it’s where we live and its atmosphere is special because it is very different from the atmospheres of all the other planets.

So where did the Earth’s atmosphere or “air” come from?

Scientists are unsure what the Earth’s atmosphere was like billions of years ago. The most common elements in the Universe are hydrogen and helium, and whereas there is a lot of hydrogen and helium in the atmospheres of the outer planets such as Jupiter and Saturn, the Earth’s atmosphere is very different.

Hydrogen and helium are light gases and they escaped very early in the Earth’s history. Eventually they were replaced by carbon dioxide, some nitrogen, and water coming out of the Earth from volcanic eruptions along with smaller amounts of sulphur oxides and very small amounts of ammonia and methane.

But the atmosphere is very different today than it was then.

Today, the ingredient that makes our atmosphere different from all the other planets is oxygen. It is a rather large proportion of air (about 21 per cent). Initially oxygen may have been formed in small amounts by sunlight breaking up water molecules (H2O) in the atmosphere. Today most of the oxygen comes from photosynthesis driven by the engine of life that converts water into oxygen. If there was no life on the Earth, then we estimate that the amount of oxygen in our air would be billions of times less than what it is today.

For further information contact: questions@ask-a-scientist.net

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nitrogen in foods While pondering this question, I came across an article in the Manawatu Standard from 1885 entitled The Object of Eating. In this article it was stated: “we eat for warmth and strength; hence almost all articles of food have both these elements: have carbon to warm, and nitrogen to strengthen.” To the general public this statement still rings true today. We often hear about the need to “carbo load” (to ensure one has the energy to compete in a race) and one only has to wander down the health supplement aisles at the supermarket to see that there is clearly a public association between protein intake and strength.

The reality is that the importance of nitrogen in foods is much wider than as a means of providing “strength”. There have been many advances in our understanding of the nutritional importance of nitrogen over the last hundred years, however, these will only be given cursory attention.

Instead, this article focuses on how food technologists can utilize nitrogen containing compounds to design foods that achieve targets that may be set by nutritionists, consumers, marketers, legislators and food companies.

Nitrogen for health As noted in the opening paragraph, one of the key nutritional reasons for consuming nitrogen is for “strength”.

The nitrogen consumed for this purpose has traditionally been in the form of proteins. Additionally, the proteins in turn have been consumed in a largely undifferentiated form such as “a steak”,“an egg”, or “a glass of milk”. However, the term “protein” covers a class of chemicals consisting of any combination of nitrogen containing amino acids in any number. Proteins between species and within a single species may have similarities but will have different amino acid compositions and therefore varying secondary and tertiary structures. Thus, consumers may consume a diet

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having an equivalent protein mass intake, but it does not necessarily follow that the physiological affect of the diet, protein-wise, will be equivalent.

Recognition of this fact has led food technologists to develop processes to isolate specific proteins from the “raw food” at a commercial scale thus enabling new foods to be manufactured that maximize a particular benefit to the consumer. Going back to the “nitrogen for strength” idea and perusing the body building beverage aisles, one finds that the majority of formulations contain whey protein as the protein source and there is a good nutritional reason for this: branched chain amino acids are a significant component of muscles and the whey proteins in milk are a rich source of them. An athlete/body builder consuming undifferentiated “milk protein” would not observe the same rate of muscle growth as an athlete consuming only the whey protein fraction.

Understanding the nutrition is really only one side of the equation – in order for this knowledge to have an impact on society foods must be designed that can deliver the desired outcome. In this case the specific form of protein must be available at commercial quantities.

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Food technologists can utilize nitrogen containing compounds to design foods that achieve targets that may be set by nutritionists, consumers, marketers, legislators and food companies, writes Alistair Carr, Massey University.

Why should we care about nitrogen in food?

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Isolating proteins The question then becomes: how does one manufacture these specific ingredients?

In general, to isolate a protein – in this case the whey proteins from milk (which also contain fat, casein proteins, salts and lactose) – a food technologist must find a property of the component that is different to at least one of the other components. The property may be physical, such as size or density; or chemical, such as binding constants to charged surfaces.

The next task is to create an environment that leverages this difference and thus destabilizing the system and affecting a separation. Typically in a milk system the first process chosen is one that increases the effect of gravity which results in separation based predominantly on density, and partially on fat globule size, through use of a disc centrifuge.

Centrifugation results in two product streams: cream (a low density fat rich stream); and skim milk (a high density

Figure 1: Schematic of methods for promoting casein micelle aggregation: neutralizing surface charge by acid addition and removal of surface charge by enzyme (rennet) addition.

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stream comprising casein proteins, whey proteins, salts and lactose).

Separating the casein proteins can be achieved in a couple of ways. The main physical difference between the proteins in milk is that the caseins group together to form large quaternary spherical structures (about 200nm in diameter), whereas the whey proteins are globular proteins that do not form large structures in their native state and so have a particle size of about 4nm. While this sort of size difference is not something that can be exploited in the kitchen, industrially it is possible through the use of microfiltration. In this process by pumping milk over a membrane with a small enough pore size under the right pressure good separation can be achieved. More commonly however, technologists make use of the chemical differences between casein and whey to increase the particle size of the casein proteins.

Growth of casein micelle particle size is mostly limited because the surface of the micelle has a negative charge which is strong enough to cause repulsion between micelles (Figure 1). So the two options available for creating an environment which overcomes the micellar repulsion to allow aggregation is to: a) neutralize the negative charge through addition of hydrogen ions (positive charge) i.e. lowering the pH to the isoelectric point; or: b) physically remove the negative charge with an enzyme, rennet (which incidentally is sold in supermarkets as Renco for the purpose of torturing children by promising them dessert only to give them Junket).

Upon aggregation of the casein micelles, the casein can be readily removed by filter screens in the case of method a) and with method b) after a few more processing steps, such as heating and salting, as blocks of cheese. It is worth noting that rennet, and indeed all enzymes, are in fact proteins and thus nitrogen based.

The whey protein content in the whey stream that has been isolated from the casein can be further concentrated using ultrafiltration (essentially the same as microfiltration but with smaller pore sizes) to remove lactose and salts which are more than an order of magnitude smaller in size than the whey proteins. Usually ingredients are sold as powders and so the last step in manufacturing a whey protein ingredient is to remove water. Again by manipulating the environment it is possible to separate the last of the components. In this case we make use of the difference in thermal properties to convert water to a gas and thus create a large difference in the physical property of density which allows an easy separation via gravity. However, it is not as simple as boiling off water in a saucepan on the stove. With many protein products – and for that matter food components in general – heating can result in undesirable changes. Whey protein for example undergoes irreversible denaturation at about 70°C which

Figure 2: Electron micrograph of nanostructured whey protein fibrils. (Supplied by S. Loveday, Riddet Institute, Massey University, Palmerston North)

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can result in gels and/or insoluble particles; neither of which are desirable if the final application is a drink! Two solutions to the problem of converting water from a liquid to a gas without damaging the whey protein are used in industry: • the first is by converting the water to a vapour under a vacuum in a piece of equipment called an evaporator.

Typically a sufficient vacuum is exerted such that the liquid whey stream stays below 60°C • the second solution is by creating a very high surface to volume ratio such that the latent heat of vaporisation cools the remaining components. Industrially this is achieved in a spray drier by forming tiny droplets by spraying the concentrate into a chamber along with hot air (>180°C). The droplets dry so quickly and spend such a short time in the chamber that they exit, as a powder, at temperatures of less than 70°C.

Delivery of protein Okay, so we now have a relatively pure source of whey protein which we can now use to formulate in combination with other ingredients not only sports drinks but also infant formula, bread, custards, canned soups and other food products; but it is not quite the end of the “how do we get the protein in food” story. We have the desired amino acid composition, but there is still the issue of what is the best way to deliver this protein to the body: does it matter how the protein is delivered? Recent research suggests that for some applications it certainly might. One example is the recent German Infant Nutritional Intervention (GINI) Study from which it appears that the role of infant formula is more than merely a vehicle for the supply of protein.

The GINI study suggests it may be feasible to decrease the occurrence of allergic disease in latter life through consumption of infant formulae containing hydrolysed protein. In this case the amino acid composition of two whey protein infant formulae may be identical, but rather than having all the amino acids joined together as in the naturally occurring protein, the protein is digested with enzymes which results in the protein effectively cut up into smaller pieces called peptides. The development of a process for manufacturing hydrolysates is complicated and the final product is highly dependent on the types of enzymes used and the length of time the enzymes are in contact with the substrate protein before being inactivated.

The reason many of us eat food however, is not motivated by how much protein we can consume; increasingly people are selecting foods on the basis of what they do not contain.

The big thing that people try to avoid is fat. The trouble is fat makes food taste great and contributes a creamy mouth feel that we find desirable, and people don’t really like having to compromise on taste. It turns out that nitrogen in our food can come to the rescue enabling us to have our cake and eat it. Remember the problems with heating whey proteins – the fact that it denatures and forms aggregates of insoluble protein? By understanding the kinetics of how these aggregates form, food technologists have developed processes that enable customised denaturation and aggregate formation so that the final whey protein particle size can be controlled. One such product is SIMPLESSE®. If a person eats particles with a size of between 1-20 microns the tongue interprets the particles as fat globules and there is a perception of creaminess.

While the creation of protein to form a fat mimetic operates on the micron scale the cutting edge of nitrogen in food is on the nanoscale (Figure 2). When proteins undergo denaturation there is often some form of self-assembly which typically occurs in a random fashion and may result, if growth is not controlled, in large aggregates on the microscale such as in a SIMPLESSE® style product through to macroscale protein aggregates as seen in products like cheese or hard boiled eggs. One of the disadvantages of

Is nitrogen elsewhere in our foods?

So far we have focused on the nitrogen that is perhaps most associated with food: the proteins. But the presence of nitrogen in food and throughout food production is ubiquitous showing its face in many forms such as preservatives (nitrates/nitrites), foam production (Draught style canned Guinness, aerosol canned creams), and colour and flavour development in products containing an amino bearing compound, such as protein, and a reducing sugar).

Unfortunately, there is not space in this article to cover all the areas where nitrogen is involved in food, but it is worth

noting that the involvement and impact of nitrogen is not always as obvious as seeing the brown colour in baked goods, tasting the caramel flavours in fudge or watching the foam formation in the head of a poured Guinness.

Nitrogen use in food can also be more subtle. For example, in the process of cryogenically freezing potato chips with liquid nitrogen; while none of the nitrogen used for freezing is found in the final deep fried chip, the cryogenically frozen chips have less oil pick-up during cooking compared to mechanically frozen chips and are thus both healthier to eat and have reduced cooking costs for the retailer as less cooking oil needs to be replaced after cooking an equivalent mass of chips. The reason for this difference is that the rapid freezing rate afforded by liquid nitrogen results in significantly less structural damage to the chips due to the water in the chips freezing as very small crystals. During frying, accessible water is removed and the holes thus formed are then filled with cooking oil. Unlike the slow freezing rate when mechanical freezing is utilised which results in large ice crystals, the water in cryogenically frozen chips is still predominantly contained within the cells of the potato and thus less accessible to being boiled off on cooking.

Another instance where nitrogen is perhaps less visible is its role in modified atmosphere packaging where the food technologist replaces the air in contact with a food product with a gas â&#x20AC;&#x201C; typically carbon dioxide or nitrogen. The goal of modified atmosphere packaging is to reduce deleterious reactions that require oxygen such as the oxidation of fats which result in rancid off flavours. Additionally, removal of oxygen can slow the rate of degradation by aerobic bacteria. Nitrogen gas is commonly used when packaging chippies to replace oxygen. The chippies are then normally packaged using a foil laminate which retards the rate of oxygen transfer from the atmosphere into the modified atmosphere of the chip packet.

In summary, nitrogen is of great importance to the food industry, and the food technologist must understand the chemistry, and thermophysical properties of nitrogen containing compounds and their interactions with the food environment from harvesting the raw ingredients destined for food production, during food processing, throughout the shelf life of the product to consumption and digestion by the end-consumer.

For further information contact: A.J.Carr@massey.ac.nz; and for information on how to acquire the skill set necessary to optimise the use of nitrogen in the food industry visit: http://food.massey.ac.nz/

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forming food texture through random aggregation is that it is an inherently inefficient process. It is akin to building a bridge by randomly nailing pieces of four by two together rather than building to a design that optimizes strength and resources. One can imagine that the randomly built structure will require a great deal more timber to achieve a structure with equivalent strength. It is hoped that research to control the structure of protein aggregates at the nanoscale will offer the food industry the opportunity to not only enhance viscosity and form gels at lower protein concentrations, but also result in new delivery mechanisms for nutrients and drugs. The electron micrograph illustrates the type of structures that can be formed.

The interest in nanoscale with proteins is not limited to the self-assembly of proteins to form structures but also on the ability of proteins to control the structure of other components found in foods. Some proteins, termed Anti-Freeze Proteins (AFPs) have been found to control the growth of ice by interacting with the ice crystal faces. Unilever has commercialised AFP ingredients, and successfully incorporated them into ice cream products. In another example, milk itself is a system which uses proteins, the caseins this time, to create and control the growth of calcium crystals to a size range of 2-3nm via groupings of phosphorylated serine amino acids. Milk is a supersaturated calcium solution, and if it were not for the ability of casein to form calcium nanocrystals, milk would contain large rocks of calcium which would cause blockages in the ducts of the mammary gland, mastitis and potentially death of the animal. It is this attribute of casein proteins that makes milk a good vehicle for delivery of calcium. The ability of caseins to control calcium crystal growth has also been exploited and enhanced in the teeth remineralisation product: Recaldentâ&#x201E;˘. Recaldentâ&#x201E;˘ is manufactured through selective hydrolysis of the caseins to release peptides with a high concentration of phophoserine amino acids.

ask-a-scientist createdbyDr.JohnCampbell How does acid rain form?

David Rowley, Ilam school Reimer Herrmann, an environmental chemist and hydrologist at the University of Bayreuth, Germany, who regularly visits New Zealand to work with scientists at our Forest Research Institute, responded.

The burning of fossil fuels (coal, oil and petrol) in power plants, metal smelters, homes, cars etc. produce vast quantities of waste gases such as sulphur dioxide and nitrogen oxides. When these mix with oxygen and water in the atmosphere they produce sulphuric acid and nitric acid respectively. Similarly, ammonia emitted by animals also produces nitric acid.

In heavily industrialised areas, such as in Europe and the Northeast part of America, the acid concentrations are very high. Winds can carry these acids over long distances,

perhaps to other countries, before they reach the ground as acid rain, acid snow or acid fog. Thus, lakes and rivers in southern Norway become acidified from sulphur dioxide, and nitrogen oxide from British power plants and traffic, and Dutch piggeries emit ammonia which produces nitric acid rain which falls over northwest Germany.

These acid levels are sufficiently high in many places to be harmful to plants, animals and even humans.

In contrast, the rain in New Zealand is only very slightly acidic, and then only due to carbonic acid, a weak acid which is produced when carbon dioxide in the air dissolves in water. (This is the same as occurs in gassy mineral water or in fizzy drinks). It is naturally occurring and so weak that plants and animals are not affected by it.

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nitrogen, soils and environment Agricultural productivity has been greatly increased by the use of N fertilisers, however, the accompanying risk of damaging the environment cannot be ignored, as Louis A. Schipper, Associate Professor, and Graham P. Sparling, Research Fellow, Department of Earth and Ocean Sciences, The University of Waikato, Hamilton explain:

Forms of nitrogen Nitrogen (N) is one of the essential macro-elements. Along with carbon (C), oxygen (O), phosphorus (P), sulphur (S), and a range of minor elements, nitrogen atoms are bonded to carbon and form the basis of life. Nitrogen occurs in the largest trees to the smallest microbes. It is also one of the most abundant elements on Earth. However, nearly all (about 99%) of the N on Earth exists in the atmosphere as an almost inert colourless, odourless gas.

The Earth’s atmosphere is 78% N (by volume). This gaseous N (dinitrogen gas, N2) in the atmosphere is usually not reactive. The great chemist Lavoisier found it was so inert that he named it azote, meaning without life. Gaseous N2 is ultimately the source of a wide range of other inorganic and organic N compounds, but the gas needs to be ‘fixed’ by specialist microorganisms, or converted by chemical reactions before it can enter the life cycle.

In contrast to the huge amount of largely unreactive N2 in the atmosphere, other forms of N are present in smaller quantities but are much more reactive. Examples of the reactive forms of N are inorganic compounds such as ammonia gas, ammonium salts, oxides of nitrogen, nitrates and nitrites, and organic molecules such as amines and amides, and complex proteins and humic compounds (Table 1).

Nitrogen in the environment Before human intervention, reactive N accumulated in the environment through naturally-occurring biological N fixation, and conversion during electrical storms in the atmosphere. If the latter seems surprising, remember that, globally, there are 3-8 million electrical storms each day.

Table 1: Some common forms of nitrogen Unreactive inorganic forms of nitrogen Gaseous dinitrogen in the atmosphere (often inaccurately called “nitrogen”)

Symbol N2

Reactive inorganic forms of nitrogen Ammonia (gas) and ammonium ion Nitric oxide, nitrous oxide, nitrogen dioxide, (NOX gasses) Nitrite and nitrate

NH3, NH4+ NO, N2O, NO2 NO2-, NO3-

Reactive organic forms of nitrogen The organic forms of nitrogen are a very diverse group of nitrogen-containing organic molecules including simple amino acids through to large complex proteins and nucleic acids in living organisms, and humic compounds in soil and water 16 New Zealand Association of Science Educators

Numerous, typically R-NH2

Lightning storms create NOx gasses and nitrates which ultimately find their way into terrestrial and aquatic environments. Biological N fixation by a restricted range of microorganisms results in the formation of organic N compounds, which can be decomposed to ammonium and subsequently nitrate, by another biological process − nitrification. However, reactive N compounds do not accumulate indefinitely in the environment because another important microbial process − denitrification − converts nitrate back into N2 gas completing the N cycle (Figure 1).

Biological N fixation occurs when specialist groups of microbes convert atmospheric N2 to organic forms of N (typically R-NH2). For example, Rhizobium bacteria form a symbiotic association in the root nodules of legume plants. The plant supplies the Rhizobia with carbohydrate in exchange for the soluble N compounds “fixed” by the bacteria from atmospheric N2. Within New Zealand, fixation by Rhizobia associated with clover is the dominant biological fixation process. However, in other parts of the world, particularly tropical rice-growing areas, large amounts are fixed by the fern Azolla which grows in rice paddies, and forms a mutual association with the Cyanobacterium Anabaena which grows in cavities within the fern leaf, and fixes nitrogen. Some Actinomycetes (now termed Actinobacter) can also fix nitrogen gas, and form nodules on the roots of Alder trees, again supplying N to the tree in exchange for carbohydrates derived from photosynthesis.

In contrast to the small specialist groups of microbes that fix N2, virtually all soil microorganisms are able to decompose organic forms of N to inorganic NH4+, a process known as mineralisation, or ammonification. Any released NH4+ is available to plants and microbes for growth. Depending on the C:N ratio of the organic source, the NH4+ can be immediately taken up by plants and microbes (immobilised) or released in the soil. Generally organic substrates with a C: Table 2: Global increase in reactive N (Tg N y-1) between 1860 and 2000 (adapted from Galloway et al., 2003).

Mechanism Biological fixation Fossil fuel combustion Haber Bosch Total

Year 1860

2000

15 <1 0 15

33 25 100 158

Box 1: Fertilisers versus urine patches In pastoral systems improved legumes and nitrogen fertilisers have boosted productivity. These systems can also leak N into the environment, but most of this comes from concentrated N in urine patches deposited by the grazing animals. It is not the original extra nitrogen that causes the problem, it is the fact that extra nitrogen grows more grass, which allows more cows, which deposit more urine. The urine patch N can be equivalent to 1000kgN/ha, is far in excess of the amount the pasture plants can take up and is an important source of NH3, NH4+, NO3-, NOx and N2O.

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Figure 1: Schema showing the principle components of the terrestrial nitrogen cycle.

N ratio of less than 20 will mineralise N, while those with a C: N ratio of more than 25 will immobilise N. Most agricultural soils tend towards organic matter C:N ratios of 10–12, while forest and native bush soils tend to have C:N ratios more than 15–20. Ammonium is a positive cation that adsorbs onto soil clays and organic matter which are negatively charged. Consequently, ammonium tends to be retained in the topsoil and together with nitrate is the form of N taken up by pasture and forest plants. Some ammonia and ammonium reaches soil directly by being washed out of the atmosphere and from volcanic vents.

In the natural environment, most nitrate is formed from the oxidation of ammonium. Again, this is a microbial process but can only be achieved by a relatively small and specialist group of bacteria − the nitrifiers. The first stage − the oxidation of ammonia to nitrite − is achieved by bacteria such as Nitrosomonas species. Other bacterial species such as Nitrobacter are responsible for the oxidation of nitrite to nitrate. It is important that nitrite does not accumulate in soil as it is toxic to plants and other microbes. The bacteria responsible for nitrification are generally slow growing, not tolerant of acid conditions and require well-aerated soil. Consequently, nitrification can be slow in acid or waterlogged soils, although some soils do show nitrification at low pH, possibly by tolerant groups of autotrophic bacteria or by nitrification occurring at microsites in the soil. Once formed, nitrate being a negatively-charged ion, is not strongly bound to soil, and can consequently be rapidly washed out of the soil through leaching during heavy rain (Figure 1).

Denitrification is the process whereby the N cycle is completed and the various forms of reactive N are returned to N2 gas. The process is undertaken by bacteria and is restricted to conditions where there is a supply of NO3-, low oxygen levels and an energy source, usually organic matter. A wide range of microbes is able to denitrify NO3-.

If the reactions do not go to completion, then some N2O is also formed. The formation of N2O is of concern as N2O is

a potent greenhouse gas and over a 100 year timespan is estimated to have some 300 times more warming potential than CO2 (IPCC 1995). Some N2O can also be formed during the nitrification process. New Zealand is unusual in being a developed nation where about half of the national greenhouse gas (GHG) emissions are produced from soil and animals in the rural sector rather than from urban industry and vehicles, and that 17% of total GHG emissions in New Zealand are attributable to nitrous oxide (N2O) (Ministry for the Environment, 2005).

In the last century, large amounts of reactive N have been generated by humans through industrial and agricultural development that have supported increased food production needed for a growing population (Table 2).

Some reactive N is from by-products that occur during the combustion of fossil fuels generating NOx gasses such as exhaust gasses from combustion engines; others are specific industrial processes such as the Haber-Bosch process that converts atmospheric N2 and hydrogen (usually from fossil fuel) into NH3, some 85% of which is used to make N fertilisers. Improved land management practices and plant breeding have also increased the growth of plants such as clover to enhance nitrogenfixation.

Consequences of excess reactive N in the environment There is no doubt that mankind has benefited enormously from the use of nitrogen fertilisers and the cultivation of N-fixing plants. It has been estimated that about half the world’s current population is now dependent on the use of these nitrogen inputs. The ability to grow more crops on the same area of land has allowed the continued expansion of the human population. However, these benefits are somewhat offset by harmful effects of too much reactive nitrogen. Plants are rather inefficient at using N fertiliser and typically, only around 50% of the applied fertiliser is taken up. The rest is lost from the soil/plant system through leaching, run-off, erosion and gaseous emissions. Urine New Zealand Association of Science Educators

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Box 2: Nutrient budgets Nutrient budgeting is a method of calculating nutrient inputs and outputs for a farm, with the intention of efficient use of resources. Only the adequate amount of N needed is added to maximise economic returns, and to compensate for the N lost in harvested products (like milk) and to the environment. New Zealand farmers are encouraged to use the computer program â&#x20AC;&#x153;Overseer Nutrient Budgets Modeltmâ&#x20AC;?. Based on long-term averages, the program calculates nutrient movement on a whole farm basis according to particular inputs supplied by the user. Also estimated are the potential leaching losses and greenhouse gas emissions.

Overseertm is available free of charge and can be downloaded from: http://www.agresearch.co.nz/ overseerweb.

Table 3: Estimates (Gg y -1) of the inputs of N to the New Zealand environment in 1850 and 2000 (from Parfitt et al. 2008).

Year

Inputs

1860

2000

Pasture legumes Other biological fixation Atmospheric deposition1 Fertilisers Imports2 Total

51 20 63 0 0.04 133

461 30 175 309 38 1023

1

Mainly ammonia deposition; 2 e.g. food and animal feedstuffs.

patches deposited by grazing animals on pastures are another potent source of excess N (see Box 1).

Excess reactive N can leave the site of application and then there are a number of adverse downstream effects. N can leach from the soil into groundwater and surface waters.

Too high a nitrate concentration in groundwater reduces drinking water quality, and excess nitrogen in surface waters acts as a fertiliser causing nuisance growth of algae, and eutrophication of streams, rivers, lakes and the sea.

Reactive N is responsible (together with S) for acidification and loss of biodiversity in lakes and streams in many regions of the world.

N is returned to atmosphere by denitrification as N2 and/or N2O or volatilized as NH3. Increases in reactive N in the atmosphere lead to production of troposphere ozone and aerosols that induce serious respiratory illness, cancer, and cardiac disease in humans. Despite much of the reactive N eventually being converted back to N2 gas completing the N cycle, damage has been done along the way, and both terrestrial and aquatic ecosystems are becoming enriched in N.

A nitrogen balance for NZ The Nanjing Declaration on Nitrogen Management calls upon national governments to optimise N management in their countries. One way to identify national inputs and outputs of N is to prepare a national N balance and to identify changes over time. The N inputs to the New Zealand environment have increased substantially since around 1860 following substantial forest clearances and the introduction of European agriculture for pastoral farming, with biological fixation by pasture legumes and N fertilisers showing particularly large increases (Table 3).

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Box 3: Nitrification inhibitors Nitrification inhibitors are chemicals applied to soils to slow the bacterial conversion of ammonium to nitrate.

Ammonium, from N fertilisers, organic matter, dung and urine, is a positively charged ion and much less readily leached from soil than nitrate. By slowing the conversion of ammonium to the more readily leached nitrate, more N can be retained in the soils and N uptake by plants may be improved. Keeping the N concentrations low also reduces gaseous losses as N2O. The inhibitors such as DCD (dicyandiamide) can persist for some weeks in soil, particularly under cold dry conditions.

Table 4: Estimates (Gg/y) of the outputs (losses) of N to the New Zealand environment in 1850 and 2000 (from Parfitt et al. 2008).

Year

Outputs

1860

2000

Produce (exports) Leaching Denitrification Effluent discharge NH3 volatilisation Erosion Trees and fires Total

1 72 27 1 1 153 11 266

165 304 153 35 241 190 17 1105

The large increase in inputs has been matched by correspondingly large increases in outputs. Once exports of produce leave our shore, or are discharged to the sea they no longer contribute to the NZ nitrogen balance (but there can be some redeposition to land from atmospheric discharges).

In both years examined, inputs and losses for NZ were almost in balance, but note that in 2000 much of that balance was accounted for by leaching, volatilisation and denitrification on the losses side. These are all processes that increase the movement of reactive N through our terrestrial and aquatic environments with an associated increased risk of environmental damage.

While there is no doubt that agricultural productivity and the export of produce has been greatly increased by the use of N fertilisers, the accompanying risk of damaging the environment cannot be ignored. Some countries have considered introducing an N tax (Finland, Sweden) to discourage overuse of N, and most developed countries including NZ regulate against discharges of effluents that are too high in N. A range of techniques to moderate N inputs includes use of computer models (e.g.

Overseerâ&#x201E;˘) to optimise N application on farms (see Box 2). Other land management practices are also encouraged, such as fertiliser application only to suitable crops and soils, restoration or protection of wetlands adjacent to waterways, regulation to restrict intensive land use on vulnerable soils and areas, and possible control of some soil processes using nitrification inhibitors (see Box 3). Parfitt et al. (2008) suggest that rather than NZ aiming for greater agricultural intensification, implying greater use of fertilisers and more production, an alternative strategy would be to switch to a greater proportion of high value crops where bulk production is not the main objective.

For further information contact: schipper@waikato.ac.nz

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As part of the global imperative to reduce greenhouse gas (GHG) emissions and environmental degradation, New Zealand must address issues on excess reactive nitrogen (Nr) in its agro ecosystems, as Dr Scott Fraser, researcher in pedology/soil quality assessment at Landcare Research, explains: Introduction Since the 1960s the global use of manufactured nitrogen fertilisers has increased considerably. In New Zealand, use of nitrogen fertilisers went from 27,000 tonnes in 1987 to 355,000 tonnes in 2005, initially mostly for arable and horticultural crops and then in the dairy sector, and later in the dry stock sector up to the current recession (MacLeod & Moller, 2006). While globally there are other important sources of reactive nitrogen Nr in the environment, (see Nitrogen, Soils and the New Zealand Environment – in this issue), such as from industry and vehicle emissions, in New Zealand the use of fertilisers in the agricultural sector, and most importantly in the dairy industry, is the largest source of Nr in the environment. Phosphate (P) fertilisers are also important in their contribution to Nr in the environment, because P fertilisers are used to increase production of pasture legumes, with a concomitant increase in ‘fixed’ Nr. This article will therefore focus on fertiliser N and legume fixed N, and the ensuing Nr cascade that follows use of N and P fertilisers in New Zealand agriculture/horticulture.

While use of fertilisers has undoubtedly increased New Zealand’s agricultural primary production, the environmental consequences are increasingly bringing into question the wisdom of continued intensive fertiliser use to increase production. Part of the problem is that historically the environmental burden due to intensifying agriculture has been externalised – that is: the cost is not born by the industry, therefore there has been little incentive for the industry to take action to reduce the environmental consequences. In the Lake Taupo catchment, where tourism provides a greater source of revenue than agriculture, steps have been taken to reduce negative impacts on lake water quality by regulating N fertiliser use in the catchment. This sort of regulatory approach may ultimately be adopted throughout New Zealand if primary industry cannot be incentivised to adopt more sustainable practices around fertiliser use.

Nitrogen cascade There is a greater mass of N in the biosphere than all the other major elements (C, O, P, S) required for life combined, yet virtually all (>99%) of this is in the form of N2 gas which is unavailable to the vast majority of organisms. A very few microorganisms can fix N2 thereby making it available for living processes. However, globally, most of this reactive N – Nr now enters the biosphere through anthropogenic processes. Galloway et al. (2003) describe how Nr moves through the environment in a many step process, potentially disrupting and damaging the environment as it cascades through numerous environmental compartments, before ultimately returning as N2 to the atmosphere. It has been estimated that most of the Nr introduced to agroecosystems globally is redistributed to other systems: 50%

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as harvested crops, 23% leached, 6% volatilised as NH3, 6% volatilised as N2O/NOx with only 10% converted back to N2 in the agro ecosystem (Galloway, 1998).

In New Zealand most Nr enters the terrestrial environment via intensive agriculture either as N based fertiliser or fixed by legumes. In pastoral systems, particularly dairy, this Nr can then be concentrated onto small areas of soil through livestock urine. These very high inputs of Nr far exceed the plant requirements in urine patches and most of this Nr is lost from the pasture system as NO3 ions or NH3, or N2O/NOx gases. Managing Nr in urine patches presents one of the greatest challenges to mitigating environmental impacts of Nr in New Zealand. Losses of Nr from intensive pasture can range from 30 to 200 kg ha-1 year-1 due to leaching of nitrate (NO3). However, annual losses from urine patches may exceed 1000 kg ha-1, and has been identified as the main source of NO3 leaching from intensive livestock/pasture systems (Ledgard, 2008).

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reactive nitrogen in the environment: mitigation strategies

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Environmental impact Atmospheric deposition of Nr is an important source of contamination of natural ecosystems mostly originating from fossil fuel combustion in regions of the world with high density human populations. This is not an important source of environmental contamination in New Zealand, although there is some local redistribution, for example from intensive farmland into adjacent low nutrient natural peat land that can substantially alter these fragile ecosystems. More important in New Zealand is NO3 contamination of aquifers, particularly where drinking water is used for human consumption. NO3 leaching from agricultural land is also responsible for eutrophication of surface waters, which often leads to degradation of associated aquatic ecosystems. When negatively charged nitrate leaches through soils it is accompanied by positively charged nutrient cations such as Ca leading to their loss.

Some of the Nr that is lost from agro-ecosystems is as N2O to the atmosphere where it is a potent GHG and also responsible for ozone depletion. Much of the NO3 that is formed in soil through nitrification will ultimately return to the atmosphere as N2O whether directly from denitrification in situ or from any of the downstream environmental compartments it enters. The more environmental compartments this Nr passes through before denitrification, potentially the more damage it causes on the way, therefore mitigation endeavours should be to targeted close to the source.

Mitigation/Abatement strategies There are two main options for reducing the impact of Nr in the environment; to reduce nitrogen inputs, such as fertiliser use (efficient use), and to reduce Nr impact once in the biosphere (efficient removal). Any mitigation strategy needs to consider the N cycle if benefits from reducing impacts at one point in the N cycle are not offset by impacts elsewhere (de Klein et al., 2001). For example, reducing soil N2O emissions may lead to greater soil NO3 leaching, which may still result in N2O emissions from aquatic environments.

In this respect process-based models such as NZ-DNDC (discussed elsewhere in this issue) that simulate carbon and nitrogen cycles in soil are useful to understand relationships New Zealand Association of Science Educators

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A New Zealand Company Developing Novel Technology Methven based company, Agri Optics, are distributors of GreenSeekerÂŽ. This technology utilises optical sensors to detect changes in herbage colour that is typically closely related to plan N status (and occasionally other parameters). On-the-spot processing of information with precise delivery allows differential rates of N fertiliser to be applied across a field based on real time plant requirements.

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A combination of software and hardware components have been used to integrate spatial and temporal data into a useful management and planning tool. Data capture can be used to produce field maps of plan N status.

Agri Optics are the developers of Smart-N. This system uses WeedSeekerÂŽ technology, but has adapted it for use in pastoral systems to recognise urine patches so as to avoid application of N to these areas. This technology could potentially also be used to target application of nitrification inhibitors to urine patches.

between all GHGs emitted from soil and also NO3 leaching (Giltrap et al. this issue).

For mitigation to be most successful, a good understanding of soil characteristics will improve results as variables such as soil carbon, C:N, texture, permeability and drainage can have major influences on the N transformation processes in the soil environment. A key component of this is having accurate and detailed soil spatial information, which will allow appropriate mitigation to be targeted to sites where the greatest benefit can be realised. Currently most areas in New Zealand lack high resolution soil maps that have sufficient data to effectively manage mitigation at the farm scale. This is currently a major limitation for applying mitigation strategies at the farm scale.

There are a number of ways that N losses from pastoral systems can be reduced, including restricting grazing, use of nitrification inhibitors, optimal timing of N fertiliser application, intercepting runoff, and using low-N feed supplements. A variety of methods is outlined below that are either currently employed in New Zealand or show potential in future mitigation strategies.

Efficient use: 1. Inhibitors In soil, organic forms of N and fertiliser N go through a mineralisation process that converts these forms to ammonium (NH4), which can be taken up by plants.

Ammonium is also converted to nitrate (NO3) by many soil microorganisms which is also a plant â&#x20AC;&#x201C; available form of N. The positively charged NH4 ion is strongly held by the overall negative charge of soil, and so is not readily lost from the soil, whereas the negatively charged NO3 ion is easily leached, therefore retaining N as NH4 ions can substantially reduce soil N losses. The conversion of ammonium to

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nitrate can be slowed by nitrification inhibitors, such as dicyaniamide (DCD), which inhibit the ammonia monooxygenase enzymes of bacteria that convert NH4 to NO3. Inhibiting this reaction leads to greater retention of NH4 in soil and therefore reduces NO3 leaching.

Preliminary research indicates that nitrification inhibitors fed to animals can significantly reduce N losses from urine patches. Ledgard et al. (2008) have administered nitrification inhibitors to sheep and measured a >90% inhibition of nitrification of urine N incubated with soil. This demonstrated that there is potential to substantially reduce N losses from urine patches due to the inhibitors (DCD) being intimately associated with the urine N at the point at which urine enters the soil, thus showing great potential to mitigate urine N leaching and NOxemissions from pastoral soils.

2. Timing of application The timing of application of N fertilisers as well as application of denitrification inhibitors can have a significant effect on the rate of NO3 leaching. Menneer et al.

(2010) found that when using the denitrification inhibitor DCD to get the most effective reduction in NO3leaching, two applications at strategic times over the autumn/ winter period may be needed. Multiple light dressings of N fertiliser will allow better utilisation of Nr by plants, and therefore reduce Nr losses; although these benefits will have to be weighed up against the additional costs of multiple applications compared to a single application. There is a move by some farmers (particularly organic) towards lower input farm systems that better matches seasonal patterns to production and more efficient nutrient utilisation. While this may lead to lower farm production, in many cases this has resulted in improved profitability due to reduced borrowing and improved cash flows.

Efficient removal: 1. Denitrification walls Denitrification walls have been used to intercept shallow ground water and can greatly reduce NO3 entering surface waters. Denitrification walls are constructed by digging a trench that will intercept an area of high NO3 runoff. The walls are composed of a carbon substrate, such as sawdust, mixed with soil that will allow runoff water to pass through the wall. The organic matter reduces oxygen concentration by stimulating aerobic respiration and also supplies an energy source for anaerobic microorganisms capable of reducing the NO3 to N2 gas (or intermediate NOx gases), and can thereby remove most NO3 from the groundwater passing through the wall (Schipper et al., 2005). A key part of the design is to achieve an infiltration rate that allows enough residence time for denitrification, but does not reduce flow to such an extent that by-pass flow occurs around or beneath the wall.

2. Wetlands Wetlands, whether natural or constructed, have the potential to intercept and remove significant amounts of Nr before runoff waters enter larger surface water bodies.

So long as runoff travels through anaerobic zones where there is decaying plant material, rather than flowing over these areas, much of the NO3 entering these systems may be completely reduced back to N2 gas.

3. Standoff pads Luo et al. (2008) calculated a 10% reduction in total farm N2O emissions could be achieved when cows grazing pastures on poorly drained soils spent 18 hours day-1, for 3 months of the year (winter period when cows were not lactating) on a standoff pad, compared with pastures that were continuously stocked. This reduced the amount of urine entering the soil at a time of the year when denitrification leading to N2O emissions was highest. They also stated that reductions may be significantly increased if denitrification inhibitors were used on the standoff pad to reduce NO3 from pad effluent, and also by timing of effluent disposal to pasture to avoid times of high denitrification potential (during saturated soil conditions).

Conclusion As part of the global imperative to reduce GHG emissions and environmental degradation, New Zealand must address

Looking to natural systems for solutions In low nutrient forest systems it has been shown that virtually no NO3 is leached due to very efficient use of N by forest species. This is accomplished through plants having mycorrhizal associations, whereby the mycorrhiza can directly access organic forms of N (in plant litter), thus bypassing the soil mineralisation processes that can lead to N leaching losses. These processes are not well understood, but there is growing interest in how mycorrihizal associations with grassland species may be used to reduce nitrate leaching from pastoral systems (Leake et al., 2004).

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3. Low – N feed supplements The use of low protein feeds such as maize silage to supplement high protein pastures has been suggested as a means to reduce relative use of N litre-1 of milk while increasing production ha-1. Efficient N fertiliser use can be achieved by matching N fertiliser application to maize plant requirements. Further efficiencies can be gained when maize is used as a dietary supplement as this results in lower urine Nr deposition back on to pastures (Luo et al., 2008).

issues about excess Nr in its agro ecosystems. While Nr is critical, whether naturally or anthropogenically fixed, to continued food production for a hungry world, we must learn to use it more efficiently. This may ultimately reduce costs of fertilisation, but, more importantly, reduce losses from agriculture that can result in a cascade of environmental damage.

While significant work is currently underway to understand soil nitrogen cycles and fluxes, new information (such as accurate spatial data) and new methods need to be combined to develop effective strategies to manage Nr fluxes between the soil, other environmental compartments, and the atmosphere.

For further information contact: FraserS@landcareresearch.co.nz

References de Klein, C.A.M., Sherlock, R.R., Cameron, K.C., & van der Weerden, T.J. (2001).

Nitrous oxide emissions from agricultural soils in New Zealand - a review of current knowledge and directions for future research. Journal of The Royal Society of New Zealand, 31, 543-574.

Galloway, J.N. (1998). The global nitrogen cycle: Changes and consequences.

Environmental Pollution, 102, 15-24.

Galloway, J.N., Aber, J.D., Erisman, J.W., Seitzinger. S.P., Howarth. R.W., Cowling. E.B., & Cosby. B.J. (2003). The nitrogen cascade. Bioscience, 53, 341-356.

Leake, J., Johnson, D., Donnelly, D., Muckle, G., Boddy, L., & Read, D. (2004). Networks of power and influence: The role of mycorrhizal mycelium in controlling plant communities and agroecosystem functioning. Canadian Journal of Botany, 82, 1016-1045.

Ledgard, S.F., Menneer, J.C., Dexter, M.M., Kear, M.J., Lindsey, S., Peters, J.S. ,Pacheco, D. (2008). A novel concept to reduce nitrogen losses from grazed pastures by administering soil nitrogen process inhibitors to ruminant animals: A study with sheep. Agriculture, Ecosystems and Environment, 125, 148-158.

Luo, J., Ledgard, S.F., de Klein, C.A.M., Lindsey, S.B., & Kear, M. (2008). Effects of dairy farming intensification on nitrous oxide emissions. Plant Soil, 309, 227-237.

MacLeod, C.J., & Moller, H. (2006). Intensification and diversification of New Zealand agriculture since 1960: An evaluation of current indicators of land use change. Agriculture, Ecosystems and Environment, 115, 201-218.

Menneer, J.C., Sprosena, M.S., & Ledgard, S.F. (2010). Effect of timing and formulation of dicyandiamide (DCD) application on nitrate leaching and pasture production in a Bay of Plenty pastoral soil. New Zealand Journal of Agricultural Research, 51, 377-385.

Schipper, L.A., Barkle. G.F., & Vojvodic-Vukovic, M. (2005). Maximum rates of nitrate removal in a denitrification wall. Journal of Environmental Quality, 34, 12701276.

continued from page 18 Acknowledgements Roger Parfitt (Landcare Research, Palmerston North) and Angela Schipper (Science Learning Hub, University of Waikato) for constructive comments during the preparation of this manuscript. Part funding (LAS) was provided via Landcare Research (contract ‘C09X0705 - Sustaining Soil Services’).

References Galloway, J.N., Aber, J.D., Erisman, J.W., Seitzinger, S.P., Howarth, R.W., Cowling, E.B., & Cosby, B.J. (2003). The Nitrogen Cascade. BioScience, 53, 341-356.

Intergovernmental Panel on Climate Change. (1995). The Science of Climate Change: Summary for Policymakers and Technical Summary of the Working Group I Report, page 22. Global warming Potentials http://unfccc.int/ghg_ data/items/3825.php Nanjing Declaration on Nitrogen Management. Third International Nitrogen Conference, Nanjing, People’s Replublic of China, 12–16 October 2004. http:// www.initrogen.org/fileadmin/user_upload/nanjing/nanjing_declaration041016.pdf MFE. (2005). New Zealand’s greenhouse gas inventory 1990–2003. Ministry for the Environment, Wellington, New Zealand.

Parfitt, R.L., Baisden, W.T., Schipper, L.A., & Mackay, A.D. (2008). Nitrogen inputs and outputs for New Zealand at national and regional scales: past present and future scenarios. Journal of the Royal Society of New Zealand, 38(2), 71-87.

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agricultural nitrous oxide emissions Agriculture is a significant source of anthropogenic N2O emissions, as Donna Giltrap and Surinder Saggar of Landcare Research explain: Nitrous oxide (N2O), also known as ‘laughing gas’ (due to its euphoric effect when inhaled), is a potent greenhouse gas produced by industrial processes, fossil fuel combustion, and agricultural activities. Global N2O emissions amount to 17.7 TgN/y [Tg = 1012 g], of which human activities account for 6.7 TgN/y. Agriculture accounts for about 70% of anthropogenic N2O emissions. In addition, N2O contributes to stratospheric ozone depletion via photolytic oxidation to nitric oxide (NO).

Figure 1: Chemical structure of nitrous oxide.

Widely used in surgery and dentistry for anesthetic and analgesic effects, it is also used as an oxidiser in motor racing to increase engine output.

Atmospheric N2O concentrations have risen 18% since pre-industrial times from 270±7 ppb to 319±12 ppb in 2005. Despite its quite low atmospheric concentration, N2O is a long-lived gas (114 years) that produces a strong warming effect. Global Warming Potential is one metric used to compare different greenhouse gases that takes into account both the lifetime of the gas in the atmosphere and the amount of warming it causes. N2O has a 100-year global warming potential of 310; that is, over a 100-year time period 1kg of N2O causes as much warming as 310kg of carbon dioxide (CO2). Nitrous oxide accounts for about 6% of the global warming impact from anthropogenic greenhouse gas emissions.

N2O emissions are of particular importance in New Zealand due to our relatively high levels of agricultural production.

New Zealand’s greenhouse gas emission profile is very different from that of most United Nations Framework Convention on Climate Change (UNFCCC) Annex 1 (developed) countries where CO2 is the predominant greenhouse gas (Figure 2).

In New Zealand, methane (CH4) and N2O account for about half of our total greenhouse gas emissions. This is because New Zealand has a high level of agricultural production relative to the size of its population (and also a high proportion of renewable electricity generation). N2O accounts for 17% of New Zealand’s greenhouse gas emissions, compared to just 5% for the average Annex 1 countries. Agriculture is responsible for the about 96% of New Zealand’s N2O emissions and due to intensification in dairying and increased use of N fertilisers these emissions from agricultural soils have grown 22.4% between 1990 and 2007.

Managing N2O emissions while still maintaining food production at sufficient levels to feed a growing world population is a major challenge. Understanding the microbial processes and other complex interactions that produce N2O in soils is an essential step to developing mitigation technologies. Once a mitigation technology has been developed, field measurements are needed to confirm the reduction in N2O emissions, and modelling strategies are needed to extrapolate the effects from field to national scale.

How is N2O produced in agriculture?

Nitrogen (N) is an important element that is necessary for plant and animal growth. However, when there is surplus N in the soil there is a risk that it can be lost either via leaching through the soil (where it can contaminate waterways) or emitted as a gas (e.g. N2O, NH3 and N2). In addition to the environmental impacts, N-loss also represents an economic loss to farmers who pay to have N added to the soil as fertiliser.

N containing compounds can enter soils from a number of sources. Table 1 lists the size of N inputs into New Zealand agricultural soils from different sources. Historically, New Zealand farmers relied on biological N2 fixation from clover to supply N. However, in recent years, use of synthetic N fertilisers has increased dramatically. Animal excreta (dung and urine) remains the largest source of N-input into soils in New Zealand pastures as animals typically graze outside for most of the time and account for almost 5 times the amount of N received from fertiliser applications.

(a) (b)

Figure 2: Greenhouse gas emissions by gas for (a) all Annex 1 countries and (b) New Zealand.

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Measuring N2O emissions

Table 1: Sources of N input in New Zealand soils.

N source

Annual N (Tg N) 0.7 – 1.0 0.30 1.47 0.007 ~0.001

There are two major microbial processes that produce N2O in soil. The first is nitrification, in which ammonium (NH4+) ions are converted to nitrate (NO3-), with N2O produced as a by-product. The first step of this process, producing nitrite (NO2-), is performed by the bacterium Nitrosomonas.

The NO2- is then converted to NO3- by bacteria such as Nitrobacter and Nitrococcus.

N2O Ammonium Hydroxylmaine monooxygenase oxidoreductase + NH4 NH2OH [HNO] O2 ½ O2

H2O

NO2-

NO3-

The second process is denitrification, the reduction of the nitrate (NO3-) ion to N2. N2 itself is an environmentally benign gas (78% of the atmosphere is N2), but N2O is produced as an intermediate step and usually some escapes to the atmosphere before being reduced to N2.

Nitrate reductase -

NO3

Nitrite reductase NO2

-

NOreductase [NO]

N2Oreductase N2O

N2

Nitrification is an aerobic process while denitrification is an anaerobic process, so nitrification is favoured in dry soils while denitrification is favoured in wet soils. High levels of N2O emissions are possible when soil is subjected to sequential drying and rewetting events.

As well as ‘direct’ emissions (emissions that occur on-site) there are also ‘indirect’ emissions caused by N lost as ammonia (NH3) or leached NO3- that are transported away from the original site but may later produce N2O at some other location.

(a)

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Biological N2 Fixation Fertiliser Animal excreta Effluents, slurry and manures Atmospheric deposition

N2O emissions are notoriously difficult to measure as the fluxes tend to be low overall, but highly variable in space and time. N2O emissions can vary significantly within the space of a few metres due to variations in soil properties, and the fact that animal urine and dung N inputs are not deposited uniformly. In addition, N2O emissions frequently occur as brief plumes of high flux.

This means measurements need to cover a large area and a long time period in order to assess accurately the N2O emissions from a soil.

Measurement methods are often described as ‘top-down’ or ‘bottom-up’ approaches. ‘Top-down’ methods use micrometeorological techniques to deduce N2O emissions from the soil based on its concentrations in the air (Figure 3b). ‘Bottom-up’ approaches involve sampling N2O emissions close to the soil surface (Figure 3a). Usually this involves inserting a sealable chamber into the soil and measuring the rate of N2O buildup within the chamber.

Multiple chambers are usually required to account for the spatial variability of N2O emissions.

‘Top-down’ approaches have the advantage that they are non-obtrusive and can continuously monitor integrated N2O emissions over a region of several hundreds of metres upwind of a measurement point. There are several micrometeorological techniques used (such as boundarylayer tracer, eddy-covariance and flux-gradient). The disadvantages of these techniques are the requirement for favourable weather conditions, and that it is not always possible to restrict the measurements to the area of interest.

‘Bottom-up’ approaches can be quite cheap (but labour intensive) if manual sampling is used. Automated chambers have also been devised that allow for continuous monitoring. The downside is that a large number of chambers are required to account for spatial variability, and care needs to be taken when sealing the chambers so that the conditions inside the chamber (e.g. temperature, pressure) do not become too different from the surrounding soil.

Figure 3 shows some examples of equipment used to measure N2O emissions.

(b)

Figure 3: Examples of equipment used for N2O measurements: (a) Manual gas sampling chamber, (b) micrometeorological tower.

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Accounting for N2O emissions While N2O emissions from soils can be measured directly at a paddock scale, direct measurement at a national scale is not feasible. However, in order for international agreements on greenhouse gas emissions to be made it is necessary for countries to be able to assess their total emissions. Similarly, when agriculture enters the Emissions Trading Scheme it will be necessary to determine N2O emissions produced by each participant. Methods are therefore needed to scale up paddock scale emissions measurements to farm, regional or national scales.

As a signatory to the UNFCCC, New Zealand is required to produce an annual inventory of greenhouse gas emissions.

New Zealand currently uses a ‘Tier 2’ methodology to calculate N2O emissions from agricultural soils. This involves calculating the total amounts of N input into agricultural soils from animal excreta and fertiliser application, and assuming that a fixed percentage (the ‘emission factor’ or EF) is lost as N2O. New Zealand specific emission factors based on observations from field chamber experiments are used to calculate both direct and indirect emissions.

The New Zealand inventory for 2007 included a modified emission factor to account for the use of nitrification inhibitors (see ‘Reducing N2O emissions’ below) on a small number of dairy farms.

While the ‘Tier 2’ methodology is simple to use, it does not account for the effects of soil type, climate and management practices on N2O emissions. This means that efforts to reduce N2O emissions at the farm scale may not be reflected in the national inventory.

Process-based models that simulate the underlying N2O forming processes are being developed to help understand the way different management practices can impact on emissions at both farm and national scale. These have the potential to produce more accurate emissions’ inventories, and to account for the effects of mitigation technologies at farm scale and beyond. These models require more detailed data, which may not be available at national scale.

Reducing N2O emissions The simplest way to reduce N2O emissions from agricultural soils is to reduce the N inputs into the soil. However, there is a limit to how far N inputs can be reduced without affecting production. Denitrification is the major process producing N2O emissions in New Zealand soils, and soil moisture is a major driver of denitrification. Therefore, reducing the amount of N surplus to plant requirements in soils at times of high soil moisture is the key to reducing N2O emissions.

This can be achieved by various soil, plant and animal management strategies. Figure 4 summarises the strategies for reducing N2O emissions.

N2O is not the only greenhouse gas emitted in agricultural systems. Ruminant animals produce CH4 during their digestion processes. Agricultural soils can also act as a source or a sink of CO2, depending on the management history. In addition, agricultural soils have some potential to oxidise CH4. For these reasons it is necessary to consider the impacts of mitigation strategies on all three greenhouse gases to ensure reductions in N2O emissions are not counteracted by increases in one of the other gases.

While in this section we focus on the on-farm impacts of several mitigation strategies, it is important to consider the greenhouse gas implications of mitigation strategies over the whole production system. For example, if low N supplementary feed is used as a strategy to reduce N2O emissions from grazing animals, the emissions resulting from the production and transportation of the feed will need to be considered. These types of analyses are known 24 New Zealand Association of Science Educators

as Life Cycle Assessments (LCAs) and frequently consider multiple types of environmental impacts in addition to greenhouse gas emissions.

Feeding and system management Restricted grazing is the practice of keeping animals off pastures during the wettest parts of the year to reduce damage to pastures and N2O emissions from excretal deposits on saturated soils. The animals are confined to a special stand-off pad or herd home during these times.

These animal confinement systems are designed with slatted floors so that the animal excreta can be collected and managed.

It is also possible to reduce the amount of N excreted by animals by manipulating their diet. Options include reducing the N intake by substituting low protein maize silage for fertiliser-N enhanced grass, increasing water intake (e.g. by adding salt supplements) to dilute the N concentration in urine, and increasing carbohydrate content to enhance microbial protein synthesis and reduce ammonia loss from the rumen.

Finally, it may be possible to breed animals that utilise N more efficiently and therefore excrete a smaller fraction of their N intake.

Plant and animal management Reducing stocking rates will usually decrease N2O emissions as the excretal N deposits are less concentrated and there is therefore less localised surplus of soil N to be transformed into N2O. Rotational grazing is likely to produce more N2O emissions than set stocking at the same average stocking rate due to the very high concentration of excretal-N deposits.

Timing of grazing can influence N2O emissions.

Denitrification occurs under anaerobic conditions, so N2O emissions are likely to be higher when soils are wet. For year-round grazed animals it is not practical to avoid every rain event, but in areas where soils get extremely wet during the winter months restricted grazing (see above) may be a viable option.

Plant species with greater rooting depths can take up N from deeper within the soil, which reduces the potential for N loss. Plants with high tannin contents result in a greater proportion of N being excreted in dung relative to urine (N2O emissions from dung tend to be at a lower rate than from urine).

Soil, fertiliser N, and effluent management The amount of surplus N in soils can be reduced by ensuring that fertiliser application rates are as close to the actual plant requirements as possible, and that the timing of the fertiliser application coincides with the timing of the plant N requirement. In general it is better to apply fertiliser as a larger number of small applications. Controlled release fertilisers also avoid having large amounts of surplus N in the soil for a long time and can help reduce N losses.

Denitrification occurs under wet soil conditions, so it is best to avoid fertiliser or effluent applications at times of high soil moisture. Improving soil drainage and avoiding compaction damage may also reduce N2O emissions but risk increasing NO3- losses.

Another potential technological solution is the use of nitrogen transformation inhibitors. Urease inhibitors slow down the rate of urea hydrolysis to NH4+. Nitrification inhibitors are chemicals that inhibit the transformation of NH4+ to NO3-. Not only does this reduce N2O production from nitrification, it also limits the supply of NO3- for denitrification. All potential N-loss pathways need to be considered when using N transformation inhibitors. For

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Figure 4. Strategies to mitigate nitrous oxide emissions from grassland soils (Modified from Ledgard & Luo 2008). example, nitrification inhibitors reduce N2O emissions and NO3- leaching losses but may lead to increased NH3 losses.

The reduction in transformation rates is not permanent as inhibitors eventually break down in soil, with the rate of breakdown being higher at higher temperatures. The efficacy of inhibitors also depends on soil type. Investigating the relationships between soil properties and inhibitor effectiveness is an area of ongoing research.

Conclusion Agriculture is a significant source of anthropogenic N2O emissions both globally (65–70%) and in New Zealand (>90%). Because N2O is a long-lived gas in the atmosphere, current emissions will continue to contribute to global warming for a long time into the future. Although careful management of N-inputs can to a certain extent limit N2O emissions, new technologies will be needed if further reductions in N2O emissions are to be obtained without reducing production.

For further information contact: GiltrapD@landcareresearch.co.nz

References Clough, T., Di, H.J., Cameron, K.C., Sherlock, R.R., Metherell, A.K., Clark, H., & Rys, G. (2007). Accounting for the utilization of a N2O mitigation tool in the IPCC inventory methodology for agricultural soils. Nutrient Cycling in Agroecosystems, 78, 1-14.

Ledgard S.F., & Luo J. (2008). Nitrogen cycling in intensively grazed pastures and practices to reduce whole-farm nitrogen losses. In Organizing Committee of 2008 IGC/IRC Conference: Multifunctional Grasslands in a Changing World, Volume 1, pp. 292-297. Guangdong People’s Publishing House, China.

Ministry for the Environment (2009). New Zealand’s Greenhouse Gas Inventory 1990–2007. Ministry for the Environment, Wellington.

Saggar, S., Luo, J., Giltrap, D.L., & Maddena, M. (2009). Nitrous oxide emissions from temperate grasslands: processes, measurements, modeling and mitigation.

In Nitrous Oxide Emissions Research Progress (A.I. Sheldon and E.P. Barnhart Editors). Nova Science Publishers, New York. ISBN: 978-1-60692-267-5 Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor, M., & Miller, H.L. (Eds.) (2007). Climate Change 2007: Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge and New York. 996 p.

UNFCCC website: http://unfccc.int accessed June 2010.

What is DNA made of?

Adam Clarke, King’s High School Warren Tate, a biochemist at the University of Otago, responded.

Every cell, whether it be human, plant, animal or bacterial, contains DNA. The structure of DNA is based around a backbone of carbon, linked to hydrogen, oxygen, nitrogen atoms, and it also contains phosphorus.

DNA has repeats of a smaller three-part structure, a sugar molecule, a phosphate group, and four variations of a base, containing either one or two-ring structures. This provides four types of unit structures for DNA named for the base, A (adenine), G (guanine), T (thymine) and C (cytosine). The order in which many hundreds of these different units are linked together gives the DNA ‘sequence’, and is the key to its function as an information store. In humans, information for about 100,000 different proteins are stored in this DNA code (the genes!). A huge international effort, called the Human Genome project, aimed at a cost of 3 billion dollars

to determine the order of the 2000,000,000 A, G, C, and T unit structures in our DNA. In the 1950s, James Watson and Francis Crick, working in Cambridge, England, deduced that two strands of DNA wound around each other, with the A, T, and also the G, C bases forming pairs in the centre, to provide a very regular helical structure.

Watson and Crick realised how this structure allows DNA to be accurately reproduced so that all our cells contain the same DNA structure (and information) as our very first cell.

I hope this helps your understanding of this exciting molecule which today is the subject of an enormous research effort, stemming from the time recombinant DNA technology (genetic engineering) came on stream through the late 1970s and 1980s. This enabled DNA to be studied much more easily.

For further information contact: questions@ask-a-scientist.net

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global nitrogen cycle and the impact on the atmosphere of agricultural intensification Food production is at the heart of defining sustainability for humanity, i.e. the “capacity to endure” for the long-term, which implies there is little or no damage to the environment and a “healthy” Earth system is maintained. In this issue on nitrogen, Mike Harvey from NIWA explores the linkage between the greenhouse gas nitrous oxide (N2O) and sustainable agriculture.

What do atmospheric measurements of N2O tell us?

Nitrous oxide concentrations have been measured in clean air coming off the ocean at the NIWA monitoring station at Baring Head1 near Wellington since 1998; at the beginning of the record the concentration was about 313ppb (parts per billion2). Since then, there has been a steady rise in concentration, and by 2010 the concentration had increased by about 9ppb to 322ppb. However, to gauge the significance of this rise, we need to compare to measurements made elsewhere around the globe. There is a global network of in situ greenhouse gas measurements coordinated by the World Meteorological Organisation (WMO) under their Global Atmosphere Watch (GAW) programme.

The GAW programme promotes systematic inter-calibrated observations of global atmospheric composition. Figure 1 shows the sites reporting N2O measurements to the network. Because of its remote location on the globe, New Zealand (right on the edge of the map!) makes an important contribution to this network through its atmospheric observatories operated by NIWA at Baring Head (near Wellington) and at Lauder (in Central Otago).

Figure 2 shows the steady rise in concentration measured globally over the last decade. This summary plot of monthly averages comes from a group of stations that form part of the US National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory (ESRL) network of sites that measure trace compounds in the atmosphere once an hour. The steady rise tells us that there must be an imbalance and that we are adding nitrous oxide to the atmosphere faster than it is being removed. Concentrations in the Northern Hemisphere are consistently higher than in the Southern Hemisphere indicating that there is a greater source of this gas in the North.

More detail on Baring Head is given in the NZ Science Teacher V120 issue on carbon.

2 ppb is molecules of N2O per thousand million molecules (mole fraction) in dry air. This is 1000 times smaller than the ppm unit used for CO2 measurement.

1

Figure 1: The WMO Global Atmospheric Watch (GAW) stations that report N2O measurements.

Source: http://gaw.empa.ch/gawsis/default.asp

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the natural sources and sinks of N2O in the atmosphere are thought to have been roughly in equilibrium, at about 10 Tg N2O-N per year.

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Figure 2: Nitrous Oxide (N2O) hemispheric and global monthly means from the NOAA/ESRL halocarbons in situ programme. From measurements made at Barrow, Alaska; Summit, Greenland; Niwot Ridge, Colorado; Mauna Loa, Hawaii; American Samoa; South Pole. This work was funded in part by the Atmospheric Chemistry Project of NOAAâ&#x20AC;&#x2122;s Climate and Global Change Program. ftp://ftp.cmdl.noaa.gov/hats/n2o/insituGCs/CATS/global/

Can we look back in time at historical atmospheres?

Small bubbles of air become trapped in the polar ice sheets as the ice accumulates. By careful drilling down into the ice sheet and extracting air trapped in the bubbles, it is possible to look at past composition of the atmosphere, at the time when the bubbles were sealed into the ice. Figure 3 shows results of this look back in time. There is evidence (inset) that the N2O concentration starts to rise more steeply after 1700, at the time when agriculture was starting to become more productive and mechanised. Prior to this,

Nitrous oxide is a long-lived GHG with an atmospheric lifetime of >110 yrs.

Nitrous oxide is a potent GHG with a greenhouse warming potential of ~300 times greater than CO2 (over 100 year time horizon).

Natural sources and sinks are thought to have been roughly in equilibrium prior to the industrial revolution. Since the industrial revolution, the N2O source has increased by 40-50% and the gas has accounted for about 6% of the enhanced greenhouse effect attributed to long-lived gases.

In addition to its greenhouse effect, N2O is also important as an ozone depleting substance through its role as a source of reactive nitrogen to the stratosphere.

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Where are the natural sources and sinks?

Figure 4 shows how nitrogen cycles between the atmosphere and land (or ocean surface). Conversions within the natural cycle of nitrogen are facilitated by microorganisms i.e. bacteria and archea. Biological nitrogen fixation by micro-organisms known as diazotrophs can take nitrogen from the atmosphere and convert it to ammonium, which provides nitrogen in a form that is available for plant growth. Nitrifying micro-organisms in soil and ocean oxidise the ammonium into more mobile forms of nitrite and nitrate and some N2O can be released in this process.

In anoxic environments, denitrifying organisms utilise oxygen from the nitrate and these conversions result in the

Figure 3: Average levels of N2O in the atmosphere since 1700 (Year 0 in inset), expressed in ppb. Contemporary measurements commenced in 1978 at the laboratories of the NOAA, and earlier measurements are based on air extracted from Antarctic ice and firn (compacted snow) which traps and preserves the air of historical atmospheres. Contemporary data are available through the World Data Centre for Greenhouse gases: http://gaw.kishou.go.jp/wdcgg/. The historical sources have been compiled by Holland et al. [2005] and are available online from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. http://daac.ornl.gov/. Extension of the record back 2000 years B.P. has been achieved from samples retrieved from ice cores collected at Law Dome, Antarctica [MacFarling Meure et al., 2006].

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Figure 4: The cycling of nitrogen between atmosphere and soil.

Figure 5: This contour plot shows the concentration of N2O thorough a south-north slice of the Pacific atmosphere measured by the Hiaper Pole-to-Pole Observations (HIPPO) http://hippo.ucar.edu/ in November 2009. The colour bar shows N2O concentrations in ppb. The contour lines are potential temperature (Kelvin). The in-situ measurements are made by quantum cascade laser. Data provided by Eric Kort and Steven Wofsy, Harvard University. HIPPO is supported by the National Science Foundation (NSF) and its operations are managed by the Earth Observing Laboratory (EOL) of the National Center for Atmospheric Research (NCAR).

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Figure 6: Global production of synthetic fertiliser and manure production. These data have been compiled by Holland et al. [2005] and are available online from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. http://www.daac. ornl.gov. Recent data are provided by the Food and Agriculture Organisation of the United Nations: http:// faostat.fao.org production of N2O and molecular nitrogen which returns to the atmosphere to complete the cycle. Tropical wet soils are thought to be a significant natural source region.

Recently, a group of U.S. scientists co-ordinated through the National Center for Atmospheric Research (NCAR) in Boulder, Colorado have been making airborne observations through slices of atmosphere over the Pacific Ocean with the aim of identifying the major source and sink regions of greenhouse gases.

The experiment called “HIPPO” (Hiaper (the aircraft) Poleto-Pole Observations http://hippo.ucar.edu/) is providing new insights with Pole-to-Pole slices of atmospheric composition. Figure 5 shows data from the flight in November 2009. In common with measurements at other times of year, the plot shows more N2O in the Northern Hemisphere than to the South. A significant source of N2O from tropical land has been lofted and shows up in the figure as elevated concentrations in the tropical midtroposphere. Nitrous oxide is a relatively stable molecule in the lower atmosphere, and the main loss mechanism is through breakdown (photolysis) by ultraviolet radiation in the stratosphere (upper atmosphere – well above 10km).

Uplift in the tropics is likely to be a major path through which N2O finds its way into the stratosphere.

Fertilisers, global population and the “Green Revolution” In the early 20th century, a German chemist Fritz Haber, developed the capability of synthetically converting atmospheric nitrogen (which makes up 80% of the atmosphere) into ammonia. The process was industrialised in 1913 by Carl Bosch, and the two were subsequently awarded Nobel prizes. This remarkable development, known as the Haber-Bosch Process, is a key step in the production of synthetic nitrogen fertilisers. Figure 6 shows how production has grown over the 20th century, in particular following World War II. Fertilisers have been a key component of the so-called “Green Revolution” of agricultural intensification that has only been possible through the combined scientific and technological advances of high yielding crops from plant breeding programmes, agrochemicals for pest and disease management and synthetic fertilisers. Since World War II, global population has trebled from about 2.3 Billion in 1940 to 6.9 Billion today. Synthetic fertiliser is thought to sustain

Figure 7: The magnitude of the global sources and sinks of N2O as summarised by Denman et al. [2007]. about one third of the current global human population.

The increased fertiliser use, along with intensification of animal farming to feed the growing global population, is driving the sharp increase (Figure 3) that we are now seeing in nitrous oxide in the atmosphere.

How do the natural and anthropogenic emissions compare?

Recent estimates from the Intergovernmental Panel on Climate Change (IPCC) [Denman et al., 2007] are shown in Figure 7. Soils under natural vegetation account for 60% of the natural source of 11 TgN per year; agricultural accounts for 40% of the anthropogenic emissions of 6.7 TgN per year. The sum of these sources exceeds the stratospheric removal, thought to be around 13 TgN per year, leading to accumulation and increasing concentrations in the atmosphere. This is of concern as N2O has become the third most important greenhouse gas in the atmosphere.

The future: Where to for nitrogen management?

The second “Green Revolution” will need to focus on sustainable intensive food production with lower fertiliser input. Nitrogen use and management is a key component.

Integrated studies are developing to look at what governs whole plant nitrogen response in order to develop a better understanding of nitrogen use efficiency. Plant breeding and improved root systems are one key focus of research.

However, it is not just plant breeding, but an understanding of the whole production system that is required. For instance, pioneering research at Lincoln University has been looking at improving nitrogen retention in soils through the use of nitrification inhibitors. Biological nitrogen fixation by clover in the pasture can supply the majority of the nitrogen in the clover top growth. Some of this N can be recycled back to the pasture by the grazing animals and is available to support grass growth, reducing the need for additional fertiliser application. If this N can be better held in the soil through the use of inhibitors that limit the conversion to nitrate and reduce leaching, then the need for fertiliser is reduced further still.

For further information contact m.harvey@niwa.co.nz

References Denman, K.L., et al. (2007). Couplings between changes in the climate system and biogeochemistry, in Climate Change 2007: The Physical Science Basis.

Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by S. Solomon, et al., Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Holland, E.A., et al. (2005). Global N Cycle: Fluxes and N2O Mixing Ratios Originating from Human Activity, edited, Data set. Available online [http:// www.daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. MacFarling Meure, C., et al. (2006). Law Dome CO2, CH4, and N2O ice core records extended to 2000 years BP. Geophys. Res. Lett., 33(14), L14810.

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teaching and learning about controversial science issues The overarching Nature of Science (NoS) strand in our revised science curriculum presents teachers of science with a number of challenges. One of them is the ‘Participating and Contributing’ achievement aim with its focus on controversial science issues (CSI). This article reports on a new classroom model for exploring controversial science issues with students that was trialled in New Zealand science classrooms, writes Dr. Kathy Saunders, the University of Waikato.

Introduction Some incidents in teaching can be life-changing. A few years ago, while facilitating a meeting with local Heads of Science, I mentioned an issue that had risen locally regarding genetic engineering and suggested that this would be exciting to explore with their students. One of the Heads of Science became agitated and started to shout that this was not science and “over my dead body will I teach such rubbish!” He then left the meeting and did not return. I discussed this with the group, and it became clear, for a number of reasons, that not all teachers were feeling confident about teaching issues in their classrooms, and there were some that also did not think that it was “science” to do so. I had further informal discussions with teachers in a range of venues, and began to think that the idea of teaching CSI needed further exploration.

The recent rapid rate of scientific and technological progress has presented society with many new CSI. People, especially our students, need to be equipped with decision-making skills to enable them, as citizens, to be sufficiently scientifically literate to make well-informed decisions about problematic issues such as climate change, genetic screening, genetic engineering, cloning, alternative fuels and environmental degradation. There have been shifts in science curricula internationally, including New Zealand, towards a focus on scientific literacy. In the New Zealand Curriculum (NZC) the science essence statement asserts that students will “explore how both the natural physical world and science itself work, so that they can participate as critical, informed, and responsible citizens in a society in which science plays a significant role” (p.17). The overarching unifying Nature of Science strand of the NZC has an Achievement Aim of ‘Participating and Contributing’ which has a clear statement of intent regarding the teaching and learning about CSI at a number of levels. Teachers are expected to address these explicitly, but there are no guidelines on how they may be taught, or how ethical decisions are made. This has enormous implications for New Zealand science teachers.

As a result of these deliberations, I decided that it was important to establish the current status of teaching and learning about CSI in New Zealand and to explore whether some form of support might be useful to assist teachers to meet these curriculum requirements. I carried out a survey of secondary science teachers in New Zealand, followed up with interviews with some survey participants (Saunders, 2009) and it became clear that teachers needed pedagogical support to increase their confidence

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to address CSI in their classrooms. I then developed and trialled a teaching model to support inquiry into CSI with a small group of New Zealand secondary science teachers.

Designing the model The first phase of the project focused around the development of a model for inquiry into CSI. The design of the model was informed by data from the New Zealand survey and interviews (Saunders, 2009) and the theoretical perspectives in the international literature based around scientific literacy, frameworks of ethical thinking, and existing approaches and teaching models for addressing CSI. One of the main difficulties in developing a model for inquiry into CSI concerned frameworks of ethical thinking or reasoning − the area involved in how critical thinking is used to make a rational decision. Students require explicit instruction on ethical thinking, either before or during the context of the issue being studied, and this requires teachers who are also adept at applying ethical thinking frameworks.

There is no one universally-accepted framework for ethical thinking, and after examining and comparing the contributions and challenges of the established ethical frameworks − including those of Beauchamp and Childress (1993) − I decided to further develop the four frameworks presented by Reiss (2006). These are: • A Consequences framework, which weighs up the benefits against the harms or risks of the consequences of an action. It promotes the common good to help everyone have a fair share of the benefits in society, a community or a family. It could be seen as ‘right’ to override the rights of individuals in order to bring about happiness in the wider community.

• An Autonomy framework, which is about making decisions for yourself, and having the right to choose.

Respecting people’s autonomy (independence) and decision-making abilities enables individuals to make reasoned and informed choices.

• A Rights and Duties framework, which defines what people can expect as their right, so far as it is under the control of people or human society. There is always a duty associated with a right, though in many cases the duty on other people is simply that they do not interfere with or prevent others claiming their rights. Any right an individual has relies on other people carrying out their duties towards that individual.

• A Virtue or care-based ethics framework, which acknowledges virtues valued in society such as honesty, truthfulness, courage, fairness and compassion. It is independent of any consequences of the action.

These ethical frameworks can be viewed on a short and clearly explained video introduced by Michael Reiss (2006a) on: http://www.biotechlearn.org.nz/themes/bioethics/ video_clips.

Another ethical framework − Pluralism Today’s classrooms are increasingly diverse. However, none of the above frameworks consider ethical thinking in terms of multiple identities including cultural, ethnic, religious, spiritual or gender perspectives. I added a

Setting the criteria for the model I thought it was important to establish criteria for the development of the model for ethical inquiry. The model needed to provide opportunities: • to develop an understanding of the science concepts backgrounding the issue • for student engagement and awareness of the issue • for individual reflection on personal values related to the issue • for participation in classroom discussion, conducted within agreed parameters, e.g. no winners or losers, respect for different viewpoints, no interruptions, critiquing the viewpoint not the person • to increase awareness of how to phrase an ethical question • to increase awareness of ethical reasoning using a range of ethical frameworks. It was important to move students away from “gut” thinking to reasoned decision making • to use decision-making frameworks to scaffold students in organising their thoughts and justifying their decisions • for students and teachers to reflect on their learning (metacognition) and take action if appropriate • for teachers to use of a variety of appropriate student centred strategies and approaches to consider at various stages of the model • for teachers to shape focus questions and prompts that could facilitate, model and encourage critical thinking in students.

Trialing, critiquing, and co-constructing the model The second phase of the project involved the delivery of two full-day professional learning workshops, eleven weeks apart, with classroom trialling of the model between each workshop with a range of classes from Year 9-13. There were four teachers who trialled, critiqued and co-constructed the model. The final version of the trialled model is shown in Figure 1.

The model (see Figure 1) takes teachers and students through a series of coloured, sequential stages which are positioned centrally. Starting from the beginning of the inquiry process and based at the bottom of the model, the first stage is one of teacher preparation where teachers consider what they need to background their understanding of the issue, what resources would be needed, and then planning the unit to link with curriculum and school requirements. The model continues to move through a series of stages from engaging students with the issue, students backgrounding the science concepts behind the issue, individual values’ exploration, group discussion of the main arguments around the issue and the ethical question(s) to be addressed. A key step in the model is the stage where students focus on ethical thinking by considering the question (or statement) from the perspectives of the five ethical thinking frameworks, before making and justifying their decision. The final stage of the model is one of reflection and metacognition which could lead to appropriate action being considered in an attempt to resolve the issue.

Sidebars are colour-coded to link with relevant stages in the model. The right-hand sidebar consists of a number of strategies and approaches that might be useful at a particular stage and the left-hand sidebar presents some question-prompts to assist in questioning, to guide the teachers in thoughtful dialogue with students and to model and encourage critical thinking.

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Usefulness of the model After the teachers had trialled and co-constructed the model, they commented on the structure of the model, the change in their knowledge base, and the students’ learning.

Structure of the model The teachers found the model to be a workable and an effective tool that improved their planning and teaching of CSI in a concrete way. They found it had flexibility depending on what they had already covered with their students, and that they could vary interpretations of stages and suggestions depending on their experience. They found that the model provided a clear focus and pathway, and that its simplicity, the colour-coding of the stages of the model, the sidebars of strategies and question-and-prompts made it easy to follow and “user-friendly”. One teacher commented: It’s a magnificent vehicle for teaching science [issues] and it’s so important that we do it well because it gives relevance and meaning to a lot of stuff in today’s world.

(Harry) All of the teachers believed that the inclusion of a fifth framework of pluralism was essential in New Zealand culture in order to meet the Treaty of Waitangi obligations.

As one teacher commented, “Cultural perspectives are hugely important in the way people in New Zealand society view and see things.” (Aimee).

Particular reference was made by all teachers to the usefulness of the strategies’ sidebar. They reflected on the fact that the range of strategies encouraged and reminded them of the value of student-centred and cooperative learning strategies in providing a higher level of engagement than the teacher-centred ones they tended to use. The teachers made special mention of the value of a writing frame (see Appendix 1) as an effective scaffold to assist students to make and justify their ethical decisions.

Another helpful scaffold used by some of the teachers and mentioned in the strategies’ sidebar, was a computerbased bioethics thinking tool that I had developed in collaboration with other researchers at the University of Waikato for the Biotechnology Learning Hub. This can be found at: http://www.biotechlearn.org.nz/thinking_tools/ ethics_thinking_tool.

Teacher knowledge All of the teachers identified a significant change in their own learning about ethical frameworks and ethical decision making. Most reported knowing very little, if anything, about ethical thinking before the workshops. They commented on their enjoyment in the activities for learning about and using the ethical frameworks and all wanted to know more in order to develop this area of their teaching.

One teacher commented: I really enjoyed learning about and applying the ethical frameworks myself! My own knowledge has increased.

I’ve become quite passionate about it. I now critically listen to people’s reasons for things and am better equipped to argue their reasoning. (Aimee) The teachers identified and discussed the potential of the suggested student-centred strategies and co-operative approaches in the sidebar, not only for addressing science issues, but in the wider contexts of their science teaching.

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pluralism framework to the model so that these multiple identities can be acknowledged, explored and considered in the resolving of CSI. The case is strong for New Zealand society where the Ma¯ori view is given significance by the Treaty of Waitangi which requires the Crown, as a Treaty, partner, to protect te ao Ma¯ori (the Ma¯ori world) and heed Ma¯ori advice. The incorporation of pluralism in the model enables specific acknowledgement of the cultural and spiritual differences within New Zealand society, especially Ma¯ori world views which are required to be acknowledged under the Treaty of Waitangi partnership articles.

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Figure 1. used a continuum strategy for the first time…I used approaches that I haven’t used an awful lot of, but that I have used from time to time, so that was kind of exciting…thinking, ‘Yeah, well actually I could try a few of these things’. You get caught in a bit of a rut…got to get through this work.

The teachers identified their understanding of the science concepts as essential to enable them to extend discussions with students. They commented that they were now more aware of resources that could help them access the background science concepts as well as tools such as video clips, computer-based tools, useful websites, and templates for scaffolding students’ ethical thinking.

Student learning In terms of students’ learning the teachers commented that as a result of using the model and associated teaching and learning activities, their students had increased their science knowledge and their CSI knowledge and skills. In terms of the students’ ethical reasoning, most students were able to identify the five ethical frameworks of the model, and could comment on the framework that they, or others, were arguing from. They indicated that the students were able to use a range of frameworks, with the most commonly used ones for ethical justification being those of consequentialism, autonomy and virtue ethics. Harry, commenting on his Year 13 class noted: They were able to provide a balanced viewpoint on key aspects of all sides of the issue and then able to develop a personal viewpoint in their conclusion. There were some exceptional arguments.

Tina also commented: I think the students’ learning has been enhanced and challenged because this whole process has given them the opportunity to develop critical thinking.

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The engagement of the students was at a high level with students “motivated and enthusiastic,”“highly engaged and passionate,” especially those who were not normally engaged. Tina mentioned: This is just a normal mid-band, Year 10 with that range of ability and the range of work-ethic...but they all seemed to be engaged − especially with some of the boys and they were able to give well thought-out reasons for their viewpoints. Engagement was high. Those students, who often do not participate in more formal lessons, took an active part in discussion.

The students reflected on their learning (metacognition) and were able to identify that they had learned about ethical decision making, and how to defend their viewpoint. One student commented on her choice of ethical framework: I thought about the greater good and how many benefits there would be. I also thought about being a good kind person, sympathetic to those suffering from malnutrition. (Year 9) And another student stated: It was very interesting learning about the types of argumentive [sic] thinking...it triggered a critical form of thinking inside my mind. (Year 9) In terms of social outcomes, students frequently commented that they were able to appreciate other viewpoints, and the students also made several references to their interest in other people’s perspectives. They stated how it was useful to be in “other people’s shoes”: I could put myself in other people’s shoes and feel how other people view the issue. (Year 12) Unexpected learning All of the teachers commented that they had not expected such a high level of engagement of the students, nor had they expected the students to be able to work so easily with the five ethical frameworks, including their ability to “think

Conclusions The model provided clear, specific advice for teachers about a teaching sequence by: • providing a clear pathway of progressive steps with associated strategy and questioning sidebars for teachers and learners to work through. Later with increasing confidence, teachers creatively built in feedback loops and even omitted stages • promoting five alternative lenses through which to view ethical decision making • promoting appropriate action as a consequence of decision making and maybe with feedback from the action recycling through the model.

Teachers using the model resulted in student learning that demonstrated: • an increased understanding of the science concepts associated with the issue • a high level of engagement and motivation • an increased understanding of ethical knowledge enabling them to make and justify informed and reasoned ethical decisions • a high level of sensitivity, respect and tolerance to the wide range of views that people hold on various issues.

The model also supported the wider intentions of the NZC by: • supporting teachers in addressing the ‘Participating and Contributing’ achievement objectives of the Nature of Science strand • enriching teachers’ effective pedagogies (as required by NZC, p.34). They were more inclined to involve critical thinking, reflective thought and action, value cultural diversity and promote student-centred activities

• supporting teachers to encourage, model and explore values (NZC p.10) by giving students opportunities to express their own values, explore with sensitivity and respect the values of others, critically analyse values, negotiate solutions and make ethical decisions and act on them • contributing to the development of key competencies as mentioned in the NZC (p.12) for example thinking about the challenging questions presented by society today as a critical and metacognitive process; relating to others by recognising different points of view, negotiating and sharing ideas; and participating and contributing with informed, active involvement in local, national and global issues • enabling teachers to acknowledge obligations towards the Treaty of Waitangi by considering more than one world view (NZC p.9) • working towards the vision of the NZC (p.8) for students to become critical thinkers and informed decision makers who will be confident, actively involved lifelong learners.

Overall, use of the model showed that within the small scale of this study it supported and assisted teachers to develop their confidence and pedagogical base in addressing CSI in their classrooms, to meet curriculum requirements of both the science learning area and the wider curriculum, and move towards developing their own and their students’ scientific literacy.

For further information contact: kathy@waikato.ac.nz

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Acknowledgements I would like to acknowledge the four teachers (their names here are pseudonyms) who participated enthusiastically and so thoughtfully in this study. Thanks also to Miles Barker and Rose Hipkins for their ongoing encouragement.

References Beauchamp, T., & Childress, J. (1983). Principles of biomedical ethics (3rd ed.). New York: Oxford University Press.

Ministry of Education. (2007). The New Zealand Curriculum. Wellington: Learning Media.

Reiss, M. (2006). Teacher education and the new biology. Teaching Education, 17, 121-131.

Reiss, M. (2006a). Video - Common ethical frameworks. Retrieved May 16, 2008 from Biotechnology Hub: http://www.biotechlearn.org.nz Saunders, K. (2009). Engaging with controversial science issues – a professional learning programme for secondary science teachers in New Zealand.

Unpublished doctoral thesis, Curtin University of Technology, Perth, Western Australia.

a famous British physicist. On this scale the absolute lowest temperature is set at zero degrees Kelvin, and the temperature at which water solidifies into ice is fixed at 273 degrees Kelvin.

This is usually written as 273K. On this scale nitrogen liquefies at 77K and the liquid becomes solid at 63K. Only 3 light gases remain as gases below that temperature.

Neon, a gas used in red neon signs and lasers, liquefies at 27K, hydrogen liquefies at 20K and the lowest temperature for a gas is helium which liquefies at just over 4K. Scientists can use tricks to get to even lower temperatures.

For example, if we pump the gas away from above liquid helium it cools to below 2K. If a man-made form of helium atoms is used (called He3 isotope) the temperature can be reduced to 0.3K. I do this regularly to cool a very sensitive heat detector and so the lowest temperature produced in New Zealand is in my laboratory.

For further information contact: questions@ask-a-scientist.net New Zealand Association of Science Educators

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ask-a-scientist createdbyDr.JohnCampbell Is there anything colder than liquid air?

Beth Butel, Ilam School John Campbell, a physicist at the University of Canterbury, responded.

Yes, quite a few things are colder than liquid air. Solid air is one.

Beth, we need to set up a scale to compare the temperatures of different objects. The one we use every day is the Celsius scale which is named after Anders Celsius of Sweden. On this scale water freezes to ice at 0 degrees Celsius and water boils to steam at 100 degrees Celsius.

The coldest temperature in a house is in the freezer and is about 18 degrees Celsius below zero. This is usually written as -18°C. On this scale when we cool the nitrogen gas in air it finally becomes a liquid when cooled down to -196°C. The lowest temperature possible is minus 273 degrees Celsius. To avoid using minus numbers scientists often use another scale named after Lord Kelvin who was

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in other people’s shoes.” Ross mentioned that he had not expected the students to be able to: attack the issue as opposed to the person...they were just so enthusiastic about it and getting into it and making sure that they weren’t having a go at the person, but at the issue.

The teachers were unprepared for the depth of discussion and analysis which they considered “outstanding” and “thoughtful” and the confidence with which the students presented their views. Finally, they were surprised at the level of enjoyment of the students, and how some students thought that working with issues could be an interesting career.

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introducing and expanding a futures focus in science classrooms The New Zealand Curriculum requires schools to include a futures focus as a foundational principle in curriculum design and implementation. Cathy Buntting from the University of Waikato introduces a conceptual framework and online resource that can be used to incorporate futures thinking into a range of science education programmes.

Futures thinking involves a structured exploration into how society and its physical and cultural environment could be shaped in the future, and the development of possible, probable and preferable scenarios.The following perceptions are important: the future world will likely differ in many respects from the present world; the future is not fixed, but consists of a variety of alternatives; people are responsible for choosing between alternatives; and small changes can become major changes over time (Cornish, 1977). A strong argument for exploring these concepts in classroom programmes is to empower individuals and communities to envisage, value, and work towards alternative futures. In science education in particular, there is significant scope for including futures thinking as part of students’ exploration of socio-scientific issues. Arguments for doing so include increasing student engagement, developing students’ values discourse, fostering students’ analytical and critical thinking skills, and enhancing students’ key competencies.

This paper presents a conceptual model that can be used to help move students from being intuitive problem solvers to being better able to use scientific understandings to articulate and justify choices for a preferred future.

Developing a futures thinking model A widely cited British meta-analysis of thirteen core futures studies carried out by governments and business (DERA, 2001) found that most futures work incorporates input data, trends, drivers, outcomes, predictions, and explorations.

Scenario models of possible, probable and preferred futures are also often developed. This process appears to require at least five elements: • an understanding of the current situation • an analysis of relevant trends • identification of the drivers underpinning relevant trends • identification of possible and probable futures • selection of preferable future(s).

Key trends identified by UNESCO (2002) as shaping society include: increasing cultural differences; globalisation (where all countries are integrated into a global system of economic interdependence and cultural uniformity); increasing gender equity (leading to changes in social priorities and the way society is organised and functions); religious revival; decreasing poverty; changes in technologies (where the increasing spread of computers in homes and workplaces is changing the way people live, work and play); and advances in biotechnology (including the use of genetic engineering to create new plant and animal breeds, as well as alter human genes).

That both ‘cultural differences’ and ‘cultural uniformity’ can be included as trends exemplifies the complexity of the issues that need to be considered. In addition, whilst there may be a broad consensus about some likely future 34 New Zealand Association of Science Educators

trends, the cumulative effect of even small uncertainties means that the range of plausible future worlds is very large. A consideration of the social milieu − which both shapes trends, and is shaped by them − is also critical. Other significant drivers include demographics, environmental change, economics, science and technology, national and international governance, perceptions, beliefs, values, and attitudes (DERA, 2001). Many of these are, of course, interrelated. Similarly, the interactions between drivers and trends tend to be multifaceted and complex.

In order to demonstrate how the elements listed above can be explored in a classroom environment, a model of inquiry was developed by a team of us to help students identify relevant scientific and technological understandings in order to: • understand the current situation: What happens now, and why?

• analyse relevant trends: How does what happens now differ from what happened in the past, and why? Are the changes desirable? Who benefits? Who loses?

• identify key drivers underpinning relevant trends: What is causing the changes? Why are they occurring? Are the causes (drivers) likely to continue into the future?

• identify possible and probable futures: Are current trends likely to persist? How might they affect the future? What might change them?

• select, with justification, one or more preferable future(s): Based on answers to the earlier questions, what do you want to happen in the future? What needs to happen for this preferred future to be realised?

Each of these components can be contextualised to suit a particular topic. Thus, for a study on future foods, understanding the current situation would require an investigation of contemporary patterns of food consumption: what we eat, where we get our foods from, how our foods are packaged, and why we eat these kinds of foods.

In addition, each question is considered in relation to personal, local, national, and global perspectives. For example: What is eaten in our home, in our local community, in New Zealand, in other places around the world? The intention of this is to encourage students to think beyond how the issue affects them personally. It also emphasises the critical role of social, political and economic contexts in futures thinking, and raises awareness of the existence of multiple perspectives. An example of some of the variables that might be considered as part of a ‘future foods’ learning context is presented in Table 1. The number of variables possible within each area of the matrix, for example ‘local trend’ or ‘global driver’, provides scope for a wide range of possibilities.

Examples of classroom activities A range of teaching and learning activities can be used to enable students to explore the components of the futures thinking model. This flexibility means that different activities can be selected to engage and motivate students, clarify concepts, identify relevant scientific and technological knowledge, and foster values’ clarification and debate. Students also need to experience activities that challenge and extend their current understandings, and to be made aware of the multiple perspectives that may exist.

Future farming One of the key activities used by the Year 4 teacher to help students identify key trends and drivers in the dairy industry was a timeline obtained from the New Zealand Biotechnology Learning Hub (www.biotechlearn.org.nz).

Each student was issued with a flashcard with a date and key event in dairying development, and the class arranged themselves chronologically. The subsequent discussion focused on the changes that had occurred (the trends), and

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Table 1: Variables that might be explored as part of a ‘future foods’ learning context Futures thinking components EXISTING SITUATION What do we eat now, and why?

Settings Personal Nutritional needs for age and/or lifestyle Personal health Beliefs and values – vegetarianism, kosher

Local

National

Available choices – shops, restaurants, farmers’ markets

Cultural-specific preparation/choices of foods

Cultural influences

Regulations relating to food availability (e.g. imports) Regulations related to labelling Need for foods to improve national health

TRENDS How does what we eat now differ from what was eaten in the past?

Who benefits?

Who loses?

Changes in where we get our food (bought versus homegrown; fresh versus pre-packaged and/or processed)

Increase in the number and variety of restaurants/ take away places

Increasing choice of what is available, and from where

Rise in popularity of local farmers’ markets

Shop buying policies influence what is available

Increased variety the choices that are available

Greater availability of ‘convenience foods’ Homegrown versus bought Fresh versus pre-packaged Popularity of organically grown foods Larger number of cooking shows on television Government initiatives promoting healthier lifestyles

Global Concern over inequitable access to food

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Students’ abilities to use, critique, and adjust their thinking are also important (Conner, 2003).

Examples of some of the futures-focused classroom activities used in two science programmes are presented below. The first example is based on the experiences of a Year 4 class investigating the future of farming as an extension to a science unit on the dairy industry; the second draws on a 6-lesson programme on future foods that was implemented as a stand-alone unit with a Year 10 class.

Nutrient deficiencies Retail dominance of large corporate structures (buying policies impact on food production, ‘just in time’ marketing determines availability) Increased emphasis on ‘convenience’ – a rise in fast food outlets and ready-toeat pre-packaged foods Concern about ‘food miles’ Globalisation – increased exposure to foods from different countries/cultures Fad diets promoted by celebrities Increased emphasis on ‘convenience’ – a rise in fast food outlets and ready-toeat pre-packaged foods Concern about ‘food miles’ Globalisation – increased exposure to foods from different countries/cultures Fad diets promoted by celebrities

DRIVERS What is causing the changes?

Are they likely to continue into the future?

POSSIBLE FUTURES How might current trends affect the future?

Family lifestyles – cost, convenience

Local deficiencies, e.g. Se

Values – beliefs about what is healthy for you

Cultural influences/beliefs of a community

Awareness of personal energy and nutritional needs

Sustainability of food production and transport processes

Ability to make an informed choice regarding what is purchased and eaten Ability to afford healthy food options

Availability of specific dietary requirements in cafes and restaurants (e.g. for glucose intolerance, etc.)

Individualised nutrition - foods targeted to genotype (nutrigenomics)

Increasing diversity – different consumer groups want different foods Increase in food-related diseases (obesity, heart disease) Sustainability of food production and transport processes

Economic costs of food production and packaging Environmental costs of food production and packaging Population demographics – more mouths to feed Greater cultural diversity

Regulations affecting fast food outlets

Functional foods for specific purposes

Food subsidies – e.g. no GST on fresh food/a sugar tax

Novel foods developed

Regulated control of school lunches, e.g. only healthy options available for sale

Liquids versus whole meals Increased reliance on genetically modified foods Ability to deliver medicine through foods

Increased role for foods traditionally used as medicine – Ma¯ori rongoa in NZ PREFERABLE FUTURES

Students to make personal decisions

What foods do you want to be able to access? What about around the world?

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the implications for farmers. For example, one student pointed out: “Tankers were good; the farmers didn’t have to take their own milk to the factory,” and another explained that being able to use a rotary milking shed: “Makes the job easier because you don’t have to move.” These trends were then explored in terms of possible drivers: Why can farms have more cows than they used to? Why can a farmer now milk more cows in a day than previously?

The students’ ideas about possible and probable futures focused on the lifestyle of the farmer (reduced manual labour because of technological advancements to assist milking; greater economic advantages from being able to milk more cows) and the welfare of the animals (e.g. using video cameras in the paddocks to monitor cow behaviour and well-being). Similarly, preferred futures focused on the lifestyle of the farmer, alongside improved animal monitoring and welfare. Students’ thinking was extended and reinforced with a writing activity in which small groups moved around the class and contributed ideas in a cumulative fashion to five questions representing each of the components of the futures thinking model: What is dairy farming like these days? How has dairy farming changed? Why has dairy farming changed? What might dairy farming be like in the future? What would you like dairy farming to be like in the future?

The responses suggested that the following key concepts had been considered. Firstly, dairy farming is labour intensive, this has implications for the lifestyle of farmers; there is also a shortage of farm workers. Secondly, over time, dairy farms have become bigger in size and in number of cows. Inventions such as the herringbone and rotary sheds mean that farmers can milk more cows per day. This is good for profits. Thirdly, it is in a farmer’s best interests to keep the cows healthy. Fourthly, future changes that might make dairy farming more profitable will tend to focus on ways to enhance milk production in cows, and technologies involved in collecting the milk.

Although ‘trends’ and ‘drivers’ were not terms that the 8-year olds were familiar with, the teacher was comfortable with how she was able to introduce the language and felt that the learning would become even more powerful if the futures terms and concepts were used consistently in subsequent units. The learning could also have been extended to include political and environmental dimensions, for example, environmental impacts of increasing cow numbers on farms (e.g. effluent run-off into waterways and increases in methane gas production), and the political implications of this (e.g. the Government’s commitment to reduce greenhouse gas production). This would have allowed the viewpoints of a wider range of stakeholders to be introduced and considered, expanding the notion that a ‘preferable future’ is a personal choice, to one in which ‘preferable futures are viewed as having global implications.

Future foods A Year 10 class that engaged in a six-lesson unit on future foods was introduced to the five components of the thinking model via a range of activities. For example, a wholeclass brainstorm was used to elicit students’ ideas about the existing situation (foods that are currently available).

Students were then required to transform this information into mind maps or fishbone diagrams and to identify trends in food over time (see Figure 1 for an example of one student’s work). A whole-class discussion facilitated by the teacher helped the students to identify key drivers − factors that may have led to, or resulted in, the identified trends.

Students’ responses reflected an understanding of the concepts of change, the rapidity of some changes, and what change might/can/will bring, with ideas focusing on: 36 New Zealand Association of Science Educators

Figure 1: Work produced by a Year 10 student in response to trends in eating habits and food availability.

- increased access to fast food outlets and reasonablypriced restaurants - increased access to convenience foods (suiting busy lifestyles) - a greater variety of foods being available, including greater exposure to foods from other countries - better systems to transport food nationally and globally - health issues and greater awareness of diseases associated with poor eating habits - advertising of food products - popularity of cooking shows and recipe books - increased population growth and subsequent impact on food availability.

To introduce a values-based discussion about possible and probable future foods, students were presented with 15 examples (e.g. eggs with omega-3 added to reduce the risk of heart disease and arthritis) and asked to make a judgement about the desirability of each option. The potential to genetically modify foods using modern technologies generated particular interest. Students were then given a scenario situated in 2040 in which they were required to promote the development of a future food they had designed. Presentation guidelines helped focus group discussions on the underpinning science: describing why the food product is needed; what it is; how it works; and the benefits and risks of its development.

The teacher concluded the unit by facilitating a whole-class discussion about factors that would shape the development of foods in the future, linking the presentations to the overall aim of developing futures thinking skills. Examples of drivers, introduced by the students, included: new technologies, such as genetic modification; future research, such as identifying useful genes; the sharing of such new information; public support for these new technologies; and needs, such as feeding a growing population. This discussion highlighted the central role of drivers in shaping technologies of the future. As such, they sit ‘in the middle’ and are a key component of discussions focusing on both the existing situation and possible/preferable futures. However, there was limited exploration of wider environmental and political issues, such as environmental sustainability of food production and transport processes, and government policies related to food safety and labelling. Trends such as eating fewer refined foods for health reasons were also largely ignored. Time constraints also meant that genetic modification as a process was not explored in detail, including the complexity of the genetic modification process and the potential for unforseen (and unforeseeable) side-effects (see Hipkins, 2009).

Although the teacher of this class indicated that she had

The futures thinking tool on the Science Learning Hub The futures thinking tool on the Science Learning Hub (http://www.sciencelearn.org.nz/Thinking-Tools/Futuresthinking-tool) provides an interactive environment in which students can consider all five elements of the futures thinking model at the personal, local, national and global levels; and a record of their thinking can be inserted and saved for future visits (see Figure 2). A final screen asks students to consider their responses and explain their thinking by responding to three final prompts: • My preferred future is…

• Three reasons I think this are…

• Three reasons why others might not agree with me are…

emphasising transformational change rather than simply trend extrapolation (Burton, 2005). Such thinking is increasingly regarded as a valuable approach to dealing with a world characterised by uncertainty, with the aim being to gain knowledge and understand alternatives (Slaughter, 1995).

Important factors affecting futures thinking and learning include an understanding of the relevant science and technology; the social, political and economic factors that influence decision making; and recognition of multiple perspectives. The conceptual model presented here outlines how these might be brought together to incorporate a futures focus in science classrooms, especially where socio-scientific issues are used as the basis for the learning programme. In particular, the conceptual model can be used to form the basis of an inquiry through which students can examine issues that impact on their own and society’s future in a structured way. Having first focused student attention on the existing situation, trends, and drivers, this information can then be used to explore possible and probable futures in a manner that reduces guesswork whilst still encouraging creativity. A consideration of the social context within which the changes might take place − how people respond, react, and adapt to change − is also critical, as reflected in the multiple social levels − personal, local, national, and global − built into the model. These multiple dimensions provide an important scaffold students can use to consider the complexity and interrelatedness of systems.

The two examples presented above demonstrate that a range of engaging strategies can be used in this process.

There is also scope within the model for additional aspects, such as environmental and political factors and health and equity issues, to be articulated and considered, moving decision making from an egocentric activity to one valuing the welfare of the planet as a whole.

It is our hope that the model can be used to extend traditional approaches to science topics by linking relevant scientific and technological understandings with key futures concepts and creative thinking, and that students will be encouraged to develop critical, reflective, and flexible responses to future-focused issues that affect them as individuals and as residents in local, national and global communities.

For further information contact: buntting@waikato.ac.nz

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incorporated futures ideas into her teaching in the past, she said the unit took her“a stage further”and was“highly effective in enabling futures thinking in these Year 10 students.” She was particularly pleased with levels of student engagement, and liked the range of interactive tasks that could be used to facilitate meaningful discussion. Positive learning outcomes, as reported by the teacher, included thinking that “was at a high cognitive level as they articulated and justified their positions on preferable futures”,“tolerance of other people’s viewpoints and an awareness that there are [sic] a range of views when thinking about possible and preferable futures”, and an increase in students’ understanding about the role of scientists in developing new foods.

Acknowledgements Figure 2: The futures’ thinking tool, an interactive tool to encourage student exploration of futures’ issues (www. sciencelearn.org.nz).

Teachers can insert a futures issue designed to suit specific classroom programmes, or use the default issues: future foods, future fuels, and future medical care. In order to customise the tool to display an issue of your choosing you need to ensure that you indicate you are a teacher when you register.

The inquiry model, focusing as it does on open-ended questioning, also offers students opportunities to present and evaluate their ideas, weigh up evidence, detect bias and present and justify their decisions. Because futures thinking is inherently values-laden, it is also important that a safe and structured learning environment is created in which students can learn about the multiple perspectives that may exist; they should feel empowered to share their views, listen to one another with respect, and balance the competing needs of multiple stakeholders.

Discussion and conclusion Futures researchers help communities to envision their preferred futures and compare those visions with current trends and scenarios of possible futures (Schultz, 2003),

This work was part of a larger project carried out by Anne McKim, Cathy Buntting, Lindsey Conner, Rose Hipkins, Louise Milne, Kathy Saunders, Michael Maguire, Paul Keown, and Alister Jones (2006) and funded by the Ministry of Research, Science and Technology. We are grateful to the teachers and students who trialled these ideas in their classrooms.

References Burton, L. (2005). The fascinating future: Futures studies - past, present, and future.

Futures Research Quarterly, 21(1), 69-74.

Cornish, E. (1977). The study of the future. An introduction to the art and science of understanding and shaping tomorrow’s world. Bethesda, MD: World Futures Society.

Conner, L. (2003). The importance of developing critical thinking in issues education. New Zealand Biotechnology Association Journal, 56, 58-71.

DERA. (2001). Strategic futures thinking: Meta-analysis of published material on drivers and trends. (London: Performance and Innovation Unit, Cabinet Office) Hipkins, R. (2009). Complex or complicated change? What might biology education learn from disciplinary biology? New Zealand Science Teacher, 122, 33-35.

McKim, A., Buntting, C., Conner, L., Hipkins, R., Milne, L., Saunders, K., Maguire, M., Keown, P., Jones, A. (2006). Research and development of a biofutures approach for biotechnology education. Report commissioned by The Ministry of Research, Science & Technology. Wilf Malcolm Institute of Educational Research, University of Waikato.

Schultz, W. (2003). Infinite futures. Retrieved June 20, 2010, from www. infinitefutures.com/aboutif.shtml Slaughter, R. (1995). Futures tools and techniques.(Hawthorn, Victoria: Futures Studies Centre.

UNESCO. (2002). Teaching and learning for a sustainable future. Retrieved June 20, 2010, from http://www.unesco.org/education/tlsf/

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science education a vehicle for the key competencies in praxis WrittenbyStevenSexton ‘Key Competencies’ is one of the primary elements of the 2007 New Zealand Curriculum (Ministry of Education, 2007).

In anticipation of the Curriculum being fully implemented this year, the Ministry of Education took steps to inform teachers about the Key Competencies and to ensure they understood their intention, meaning and purpose. In addition, much has been written to better explain what, how and why the Key Competencies are central to both student learning and teacher practice (Barker, 2009; Foster, 2009; Hipkins, 2006, 2007; Hipkins, Roberts, & Bolstad, 2007; Reid, 2006; Rutherford, 2005). At the same time, however, this research has highlighted difficulties relating to the use of the Competencies in New Zealand classrooms. While commenting on science teaching in the 2007 Curriculum, for instance, Barker (2009) identified three ‘crucial’ issues concerning the Key Competencies: definition, relevance and assessment. This paper addresses these three concerns through an account of one teacher’s efforts to understand how to integrate the Key Competencies into her classroom practice.

The Key Competencies The Key Competencies are defined on pages 12 and 13 of the curriculum document. In addition, the Ministry of Education has created a rich and meaningful website (http://keycompetencies.tki.org.nz/) to aid their understanding and implementation. The difficulties arise, however, with the application of Key Competencies.

Although the New Zealand Curriculum is targeted to a nationwide audience, the individual teacher is ultimately the one who has to implement it in the classroom. Many of these teachers now find themselves in the position of having to learn the new curriculum while delivering an integrated approach to teaching. In response, a number of teachers have approached tertiary providers for support in interpreting the new curriculum and to establish ways of incorporating the Key Competencies into classroom practice.

The East Coast of the North Island has a significant Ma¯ori population, and one of the region’s local tertiary providers was founded on a social justice basis to provide educational opportunities specific to local Ma¯ori. Reid (2006) stated that social justice, with regard to equity in education, is best supported by holistic approaches to teaching. Holistic methods can work to negate the selection of knowledge that marginalizes one or more groups for the benefit of a larger dominant group. The teacher discussed in this paper wanted to develop the Key Competencies through content her students would find to be relevant, useful and meaningful and not necessarily what someone else, somewhere else deemed appropriate. This in turn addresses Barker’s (2009) concern about the relevance of the Key Competencies.

Hipkins (2007) suggests that assessment of the Key Competencies should focus on strengthening, rather than measuring, student ability. Students need opportunities to connect what they already know to what they are currently experiencing, so as to be able to build the skills necessary to “practise, persist, and overcome obstacles to immediate learning success” (Hipkins, 2007, p.4). Put simply, what teacher, parent or employer would not be satisfied with a 38 New Zealand Association of Science Educators

student who can demonstrate that they are able to: think; relate to others; use symbols, languages and text; manage self; and participate and contribute in an authentic learning environment they are then capable of translating into the wider world. Science is one way of presenting authentic and meaningful learning environments. In fact, the rest of this paper is an example of how science might be one of the best ways. Specifically, this is an example of a rich learning experience which successfully engaged and enlarged students’ competencies.

Electric circuits/Microwaves/Personal Safety: A practical demonstration During Term 3, August 2009, a teacher at a small, low decile urban school on the East Coast invited an instructor from a local initial teacher education institution to conduct a practical demonstration for her combined Year 4-6 class.

Specifically, in addition to using traditional pedagogies, this initial teacher education provider was asked to demonstrate a student-centred lesson drawing on the students’ own experiences to integrate the Key Competencies into a relevant, useful and meaningful teaching and learning environment (Macfarlane, Glynn, Penetito & Bateman, 2008; Otrell-Cass, Cowie & Glynn, 2009; Sexton, 2008).

In 2009, 99% (79 of 80) of students and 100% (6 of 6) of teachers at the school self-identified as Ma¯ori. The school unofficially operates as bilingual, with many of the classroom interactions switching back and forth between English and Te Reo Ma¯ori. As it is classified as an Englishmedium institution, the school is required to deliver the New Zealand Curriculum. Nevertheless, the legal framework of the Curriculum enables the school to draw on the Ma¯ori kaupapa (philosophy, purpose, agenda) of ako (reciprocal teaching and learning) and wha¯naungatanga (relationships, family kinship). A number of adult helpers are available to support smaller working groups within the classroom. As the class is a combined Year 4-6, older students are paired with younger students in tuakana/teina (older sibling/ younger sibling) relationships within their own classroom.

The classroom environment is rich in colour and texture and contains personalised items from each student’s home.

The students address their teachers as ko¯ka¯/whaea (foster mother/aunt) or matua (uncle or father) as many are in fact related.

The content for the demonstration session was developed in response to an event that occurred during the previous week, where a teacher inadvertently left a spoon in the bowl of soup she was heating. The microwave had only been in operation for a few seconds when sparking was noticed. Another teacher unplugged the microwave and the bowl and spoon were removed before any real damage occurred. As this caused a great deal of excitement (mainly owing to the fact the student helpers in the staffroom exaggerated the event to the rest of the school) it was decided that an electric circuit/microwave/safety session would be relevant, useful and meaningful to the students.

All of the students had had previous experience with microwaves and an idea of what their function was. When the class was asked ‘what is a microwave?’ The students generated a short list of what microwaves do: ‘heat food’, ‘cook food faster than the oven’, ‘warm up food’ and, as the

to be seen again, now that they knew that a few sparks were emitted before the grapes began to bubble and the microwave was stopped. When asked why the grapes made sparks, the students were informed that they would be asked that exact question in a few minutes.

The light bulb in a glass (half-filled with water so that the metal component was submerged) was placed in the microwave with the turntable now in place. Most said that the light bulb would turn on because that is what light bulbs do. They had not expected the light bulb to glow bright and fade as it travelled around the microwave. None seemed to grasp the idea that different points within the microwave could provide more energy to the light bulb than others. They were asked, ‘have you ever heated up food in a microwave and found some parts hot, some warm and some still cold?’ This generated a loud discussion involving several members of the class at once. The microwave was turned off and the class quickly settled. The students were then given the opportunity to discuss why the light bulb would go bright and then fade and then go bright again as it travelled around the microwave. This resulted in some of the students referring to the diagram and asking how the light bulb worked without any wires connected to it. The students were asked to explain, ‘why the grapes begin to bubble?’ They eventually got around to the idea that the water in the grapes had heated to boiling point. However, after it was pointed out that no wires touched the grapes, they were then asked, ‘but you were asked before about heating food up in a microwave and some parts not being hot and some parts hot, so does the inside of the microwave heat up like an oven or are some parts colder?’ This led to the students discussing the similarities and differences between ovens and microwaves, and they concluded that the oven’s inside is all hot but a microwave’s is not. So they were then asked, ‘as the light bulb moves from a hot spot to a cold spot, could the energy from the hot spot make it glow but then not be enough to make the bulb glow when it is in a cold spot?’ This discussion resulted in several of the students accepting this point and then encouraging the others to accept it as a CD was picked up.

As the students were told the CDs were included so that there would be sparks, all predicted that this would be the case. They were asked, ‘why are there two CDs?’ Most responded that this was so there would be lots of sparks.

They were then reminded of the two plates of grapes. Three students then proposed that the CDs would spark very quickly like the grapes, and there were two so they would know what to expect the second time. The first CD was placed in the microwave with the turning plate removed and the microwave was turned on for approximately four seconds to generate sparks before causing the plastic to burn. Once again the students discussed what happened and they examined the CD after it cooled. A second CD was ‘sparked’ to ensure everyone was able to observe the effect.

The students were then reminded that they would be asked to explain why the grapes sparked. They discussed the matter in groups with those sitting around them. After a few minutes, one group of four decided that, as the CDs sparked due to the metal inside them then there must be some kind of metal in the grapes. This was not generally accepted until one of the group’s members reminded the class of a healthy food unit on vitamins and minerals they had taken at the beginning of the year and proposed that it must be the minerals in the grapes that make them spark when in a microwave. Most of the class accepted her answer.

The final question was, ‘so who thinks they can tell the class what happened last week in the staff room?’ Nearly half the class’s hands went up. During the discussion that followed,

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previous week’s event revealed, ‘make sparks’. The students were not asked to explain how a microwave operates or why it can ‘make sparks’. The children do not need to know the physics behind what happens. They need an ageappropriate understanding of what happens when different items are placed in a microwave.

The twenty-eight students were organised into their five pre-existing mixed age and ability co-operative working groups and seated at their work stations. Each station had a battery, two wires and a light bulb. The stations were told they had two minutes to get their light bulb to stay on and, after two minutes, only two stations had managed to do this. These two groups were then asked to show the other stations what they had done so all the groups could get their light bulbs working. The resulting discussion between the groups focused on why the light bulbs had worked and what the other three groups needed to do to achieve the same. The three groups then reported back on what they had done differently that made their light bulb work.

These discussions were recorded by the teacher in diagram form on the whiteboard. As a result, the students gained a basic understanding of circuits: a power source (battery) connects (using wires) energy from the source to an object (light bulb) and this generates an effect. In this case, the effects on the light bulbs were light and heat. The students commented that the longer they held the circuit together the warmer the light bulb became.

The groups were called back onto the mat to work as a whole class. A microwave (turning plate removed) was placed in front with a no-go semi-circle (a chalk line drawn on the mat) drawn around it to indicate to the students that they could not cross this line. A slight rearrangement allowed all students to view the inside of the compartment.

Various objects were placed next to the microwave: a bar of soap, two plates of five red grapes sliced nearly in two and laid out, a light bulb in a glass of water, and two CDs. The students were asked three questions based on the diagram of the circuit drawn on the whiteboard: ‘what is the power source for the microwave?’; ‘what connects the microwave to the power source?’ and ‘what effect will this have?’ All three questions resulted in nearly everyone raising a hand to respond. Their responses were written up on a teaching board situated next to the microwave. The first question resulted in most stating the wall-plug was the source of the power. Three of the senior students responded the electricity in the wall was the source as the wall-plug had be to turned on for the microwave to work. The second question had everyone stating that the cord connected the microwave to the power source. The third question resulted in a list of ideas: light, heat, sound, cooking, and one boy asking if they were going to see sparks.

Before each item was placed in the microwave, the students first discussed amongst themselves what they thought would happen. Each item was then placed in the microwave.

None of the students predicted the soap would expand into a ‘blob’ and that it would then remain in that shape even as it was passed around after it cooled. There was no attempt to try and explain that the gas bubbles inside the soap expanded and that this caused the soap to change shape accordingly. The idea was to show the students that the microwave has different effects on different items. The soap was used later to clean hands before lunch.

The grapes were then placed inside the microwave. Some of the senior students thought the water in the grapes would bubble or the grapes would explode like an egg does. Two plates were used to demonstrate what would happen as this effect occurs quickly. The first plate showed what happened and the second plate enabled the effect

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the students explained that the metal spoon sparked like the grapes and CDs. They concluded that if the microwave had stayed on longer the sparks could have started a fire and this could have caused the school to burn down. This entire session took just over an hour.

The class then went back into their working groups, and each group was asked to illustrate and describe what had happened in one part of the demonstration. In this class the students record their experiences in ‘books’ they create.

The senior students lead the younger ones so that they all participate and contribute to the book. This also gave the classroom teacher and the initial teacher education instructor a chance to discuss what had happened and where to go next. The classroom teacher felt her students needed more opportunities like these to express their ‘thinking’ about what they were doing and how this connected to what they already knew. Although she knew that her class had problems with written literacy, she was happy about how well and enthusiastically they expressed themselves in oral language. Wha¯naungatanga, which refers to relationships, is practised daily in the school so the teacher expected the students to be able to demonstrate ‘relating to others’ and ‘managing self’. The teacher liked the idea of the demonstration as it gave the students the opportunity to ‘participate and contribute’ without having to write down what she referred to as the ‘scientific procedure’ (title, hypothesis, resources, procedure, observations, and conclusion) she normally utilised. She noted that the students began to contribute more and their depth of insight increased once they realised the science lesson was not the usual process of watching the teacher conduct a brief ‘experiment’ they would then spend a halfhour writing down.

Final thoughts This paper addressed the three issues of definition, relevance and assessment that Barker (2009) raised in regard to the New Zealand Curriculum and science education through a practical demonstration of how the Key Competencies can be combined with relevant, useful and meaningful learning experiences to construct an authentic and meaningful learning environment.

In particular, the students who participated in the demonstration were given an opportunity to connect what they already knew (about microwaves) to what they were currently exploring (electricity, electric circuits) and to make sense of this new knowledge. To achieve this, they had to participate and contribute by sharing ideas and discussing opinions with each other and the whole class.

The initial teacher education instructor kept the discussions relevant, useful and meaningful without having to go into the physics or the chemical changes behind what was happening. At the same time, the students remained engaged and not only excited about what they saw.

By the end of this demonstration, the classroom teacher

concluded the students had gained an age-appropriate level of understanding of the dangers of microwaves and what happens when certain items are placed in them. More importantly, one of the four groups was able to connect the session on electricity, microwaves and safety to a healthy food unit that was delivered nearly five months previously. Possibly one of the most important statements came from one Year 5 boy who stated, “So that is why you don’t put metal in a microwave, it can start a fire like those commercials on TV and burn down your house”.

This short statement presents an excellent example of a child being able to connect the content of a classroom demonstration to their personal experience to develop a new and personally significant insight. Rather than the usual edict of ‘do not do because I say so’, this child gained an understanding of why something should not be done.

Furthermore, the classroom teacher realised that, instead of focusing on science learning, she was able to approach learning from a science context that her students are able relate to. She plans to explore more areas of science to engage students in their learning. In fact, she followed this lesson with further enquires into what happened to the soap and how air expands when heated.

This article demonstrates how science education is a vehicle for the Key Competencies in teaching practice. The students were exposed to activities that surprised and engaged them. They were provided opportunities to explain not only what was happening but also how they understood why it was happening. These activities were deliberately chosen to build upon an event they were already discussing so as to link their home life into school life. As this article has shown, the Key Competencies are about what the teacher and students do as well as what they know.

For further information contact: steven.sexton@otago.ac.nz

References Barker, M. (2009). Science teaching and the NZ curriculum. New Zealand Science Teacher, 120, 29-33.

Foster, G. (2009). Implementing the new curriculum. New Zealand Science Teacher, 120, 34-35.

Hipkins, R. (2006). Key Competencies: Challenges for implementation in a national curriculum. In B. Webber (Ed.), Key Competencies: Repacking the old or creating the new? (pp. 17-49). Wellington: NZCER Press.

Hipkins, R. (2007). Assessing key competencies: Why would we? How could we?

Wellington: Learning Media.

Hipkins, R., Roberts, J., & Bolstad, R. (2007). Key competencies: The journey begins.

Wellington: NZCER Press.

Macfarlane, A., Glynn, T., Grace, W., Penetito, W., & Bateman, S. (2008). Indigenous epistemology in a national curriculum framework? Ethnicities, 81, 102-107.

Ministry of Education. (2007). The New Zealand Curriculum. Wellington: Learning Media.

Otrell-Cass, K., Cowie, B., & Glynn, T. (2009). Connecting science teachers with their Ma¯ori students. Set, 2, 34-41.

Reid, A. (2006). Key Competencies: A new way forward or more of the same?

Curriculum Matters, 2, 43-62.

Rutherford, J. (2005). Key competencies in the New Zealand Curriculum development through consultation. Curriculum Matters, 1, 210-227.

Sexton, S. (2008). ‘A mix of theory and practice’ and other Ma¯ori pedagogies for effective teaching and learning. Toroa-te-Nukuroa, III, 252-260.

continued from page 41 For further information contact: robert@porirua.net Readers are referred to articles written by Dr Philip Catton, Canterbury University in issues 113 to 125 for a scholarly understanding of the history and philosophy of science – Ed

References Babich, B.E. (Ed.). (2002). Hermeneutic philosophy of science, Van Gogh’s eyes, and God: Essays in honor of Patrick A. Heelan. Dordrecht: Kluwer.

Committee on Health and Social Education. (1977). Growing, sharing, learning: The report of the Committee on Health and Social Education (Chairperson J.G. Johnson). Wellington: New Zealand Department of Education.

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Eger, M. (1992). Hermeneutics and science education: An introduction. Science & Education, 1(4), 337-348.

Heelan, P.A. (1977). Hermeneutics of experimental science. In D. Ihde & R.M. Zaner (Eds.), Interdisciplinary phenomenology (pp. 7-50). The Hague: M. Nijhoff.

Kuhn, T.S. (1962). The structure of scientific revolutions. Chicago: University of Chicago Press.

Matthews, M.R. (Ed.). (1998). Constructivism in science education: A philosophical examination. Dordrecht: Kluwer.

McComas, W.F. (Ed.). (1998). The nature of science in science education: Rationales and strategies. Dordrecht: Kluwer.

Suppe, F. (1974). The structure of scientific theories. Urbana: University of Illinois Press.

Toulmin, S.E. (1972). Human understanding: The collective use and evolution of concepts. Oxford: Clarendon.

Written by Robert Shaw,The Open Polytechnic of New Zealand The 2010 SciCon Conference in Nelson was a success in many ways such as precipitating a fundamental debate between teachers about the ‘Nature of Science’.

The Nature of Science is now a compulsory part of all science teaching in New Zealand secondary schools, and yet the expression is controversial in science itself, in philosophy, in curriculum documents, and in teaching practice. The influence of the first collection of papers directed at the nature of science in science education – Bill McComas’ edited book The Nature of Science in Science Education (1998) – was apparent in some of the presentations. Thus, people sought to identify what students and teachers think science might be with some emphasis on the relationship between science and society.

There are at least three ways that the phrase ‘the nature of science’ gains expression with teachers: it may refer to the virtues or characteristics that allegedly scientists exemplify; to the methods that scientists adopt; or to the philosophy and/or history of science. As each of these three expositions of the expression itself admits of many interpretations, it is hardly surprising that some teachers at the Conference expressed frustration and asked for clear guidance on the intentions of the curriculum.

If the ‘nature of science’ refers to the virtues of scientists, then science teachers run the risk of having their subject disappear in wider school curricula. Being truthful, systematic, tidy and open to new ideas are virtues necessary in science, yet they are hardly virtues unique to science.

Our colleagues in geography, business studies, physical education, and the language subjects all subscribe to these virtues, and they incorporate them in their work with students. Such virtues are important in the community beyond the school gate. In business, on the sport’s field, and as the qualities of an employee, these virtues are momentous. An advantage of supporting these virtues is that they enable the claim that schooling is relevant to lives lived and the workplace. Somewhat more disturbing is that New Zealand only three decades ago rejected proposals to include moral education in the curriculum, whilst in one elaboration the inculcation of virtues is a task in moral education (Committee on Health and Social Education, 1977). Any proposal that science teachers are now required to inculcate moral virtues has profound implications well beyond the school laboratory. We should not underestimate the strength of belief of many New Zealanders who consider science to be the opponent of true religion or culture.

Those who interpret the ‘nature of science’ as a reference to scientific method gain strength from their assertion that there is a distinctive method which is especially the province of science. The science teacher has something unique to contribute to the school curriculum. It might be said that the method of experimentation is the province of science and definitive of its nature; this entails the formation of hypothesis, the design and execution of experiments, and the writing of research reports. Many in schools adopt this stance. Since Sir Isaac Newton this account of science has been hotly disputed: Newton himself anguished over it, and libraries are filled with descriptions and explanations about how scientists actually proceed with their work.

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Presentations at SciCon in Nelson continued to provide examples of science advancing in other ways, specifically nanotechnology, cryogenics, and space science.

Finally,we come to the‘nature of science’cast as the philosophy of science. This rendition is today closely associated with the history of science. Mention to science teachers the importance of the history of science and there are at least three interpretations extant. Some lay much store on science as an historically developing discipline. They often point to the theory of scientific paradigms which Kuhn popularised, or to Toulmin’s theory about the evolution of science (Kuhn, 1962; Toulmin, 1972). The walls of their laboratories feature Newton, Einstein, Crick, Franklin, and Watson. Other teachers believe that it is important to teach science historically; they give Democritus credit for his atomic hypothesis before they introduce Dalton and eventually arrive at Rutherford. In this they follow some of the classic textbooks of chemistry.

Their walls show science growing like a tree. A third group of teachers associates the history of science and the philosophy of science. They struggle to find in the history of science something that they can account for in (or explain through) the philosophy of science.

This brings us to the philosophy of science: if this is what people mean by the expression the ‘nature of science’ – and for many reasons I think we must mean this – the new curriculum asks a great deal of science teachers. Science is not able to question itself, and consequently science teachers qua scientists are not trained to enquire into the nature of science. Presenters at the Conference developed three accounts of the philosophy of science: positivism (often called the received view), constructivism, and hermeneutics.

They associate with important theorists (Babich, 2002; Eger, 1992; Heelan, 1977; Matthews, 1998; Suppe, 1974).

With this diversity of opinions about the meaning we may afford to the expression ‘the nature of science’, it is little wonder that teachers confront a substantial task when they first come to offer an interpretation of the science curriculum. As always, I would hope that ultimately teachers determine for themselves how to interpret the syllabi and prescriptions. This is the professional judgement of the educated and trained teacher at work. Our country will make a grave mistake if it returns to the command model for curriculum that we surpassed fifty years ago. Science teachers cannot look to others – politicians or professors – to resolve the nature of science.

New Zealand warrants no particular credit for bringing the expression ‘the nature of science’ into the science curriculum guidelines. We may find this topic in the curricula of many Western countries, and in the main it has entered those documents as a reaction to debates about social responsibility, the nature of the theory of evolution, and limitations of modern physics.

The Nelson Conference prompts these thoughts and I look forward to further explorations into the nature of science. I suspect that when teachers reflect on the nature of science it strengthens their teaching. There is also the exciting possibility that reference to the nature of science in the formal curriculum will take science teaching in new directions.

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a human biology course for 2011?

Science teachers around the country are thinking creatively as they plan for 2011. As teachers consider the needs and interests of their students, it’s becoming clear just how flexible the realigned Level 1 Science assessment matrix will be in providing a wide range and variety of possible tools for assessing against the revised NZC. There has been some concern about the fate of Human Biology in the new matrix for science. When these standards were being written we could get no definitive answer from NZQA about the fate of Human Biology as a separate subject, so the aligned standards were purposely written with the potential to allow for a Human Biology course within them, even though

there will be no separate exam. In fact, we’re spoiled for choice, as it turns out.

Let’s begin by identifying the key concepts and big ideas that we might include in a Human Biology course at Level 6. Here we set out some of the possibilities for those considering designing such a course. It is meant to be openended, in that these are not the only possibilities, just some ideas for your consideration. Remember too, NZQA suggests a course of 18–21 credits. What we have here is much more

Key concepts

Learning outcomes

Example

Systems

Understanding an organ, how it works/fails, how it interacts with other organs

Nutrition and human digestion structure & function − gut, enzymes Fail − Ulcers Absorption & circulation − the fate of food Ideas of energy ’ respiration (links to cells) Model gut, plastic trunk, pipe model of circulatory system, “Pacman” enzymes

Organisation of life − (cells), organs, organ systems, individual organism, interaction with environment How we represent structures and their functions

continued on page 43 Other directions possible

’ medical imaging to diagnose malfunction

Links B 1.5 (Mammal [human] as a consumer) P1.2 (Physics application)

’ explore further human life processes e.g. Support & movement; growth ; sensitivity; reproduction;

Life Processes MRS GREN

Understand how organ systems interact within an organism

The links between gas exchange, circulation, digestion

’ Explore further connections between interrelated systems in humans e.g. Support & movement and sensitivity; growth and reproduction;

S 1.10 (Life Processes & Env Factors)

Biotic and abiotic environmental factors affect life processes

Understand that living organs are affected by their internal and external environment

Type 2 diabetes affecting glucose balance

’ social health issues e.g. alcohol and drugs, diabetes and obesi

B 1.2 (Bio Issue)

Genetic factors such as lactose intolerance (enzyme malfunction)

’ human interactions with microbes

How science is used to inform human health and well-being

Design an investigation to measure the effect of change in physical activity level on the functioning of a human organ system

Effect of different forms of exercise on heart rate

Explore how scientists investigate factors impacting on health and well-being in our society

Effect of diet on obesity

Variation exists amongst humans

Measuring variation, record/communicate it

Genetic variation is inheritable

Distinguish between genetic & environmental origins At a very simple level

Pulse rate, foot size, eye colour, finger length, handedness etc.

Hair length vs natural hair colour

Genotype underpinning phenotype Everything either is a protein or is made by a protein Simple Mendelian patterns of inheritance Variation is adaptive when environment changes

Food poisoning ’ pattern in a pedigree/bar graph/ histogram Characteristics in your family tree e.g. eye colour

myosin, collagen, amylase, insulin, haemoglobin Can interpret pedigrees, predict phenotype ratios

Using human examples mainly

Very simple ideas of evolution

’ Antibiotic resistance

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C 1.2 (Chemistry application)

Symbiotic microbes in human gut only

Students recognise genes as recipe for protein

Human interactions with environment

S 1.11 or B 1.3 (Microbes)

Effect of pH on enzymes

How is information about health and wellbeing communicated to people?

Sexual reproduction (meiosis) & mutation as a source of variation

e.g. food preservation, pharmaceuticals, cosmetics

B 1.1 (investigation)

Humans use selective breeding to modify biotic environment e.g. food crops, dog varieties

Investigate family trees

S1.9 (Genetics)

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Steven S. Sexton, Secretary of NZASE Primary Committee At SciCon 2010, a committee was put together to offer better and more support to primary and intermediate teachers in teaching through a science context. Ian Milne has been the Primary National Co-ordinator, but decided to step down from this role. This provided the opportunity for others to step up and take on this role. It was decided that instead of one person taking on such a huge task of trying to step into Ianâ&#x20AC;&#x2122;s shoes a committee might be the better approach. As a result, the Primary Committee for New Zealand Association of Science Educators was formed under Chris Astall from The University of Canterbury.

Chris was put forward as National Co-ordinator and accepted on the condition that others support him and take on committee roles. Ian was approached to act as a mentor to both the Primary Committee and the National Co-ordinator. This committee has charged itself with helping and supporting primary and intermediate teachers in bringing more science into the classrooms in much the same way that BEANZ has for secondary biology teachers. It was decided that the first three steps would be: John Marsh (Tauranga Intermediate School) and Sterling Cathman (Nelson School District) locating and identifying the North Island and South Island science associations. They are looking to find out which primary and intermediate schools are actively involved, as well as the current points of contact for the associations. It is hoped that through these local associations more schools and their teachers can benefit like those involved with Capital City Science Educators which has taken explicit measures to include and support Primary and Intermediate science teachers.

Second is Naomi Lorimer (Blockhouse Bay) who has taken up the role as Webmaster to edit the Primary link from the NZASE website: http://www.nzase.org.nz/primaryscience. html. This will provide a gateway not only to what the Primary Committee is doing, but also other local associations. Through this Weblink, there is the intention of developing a National Primary Science Day/Week with activities each school is able to complete.

Finally, Jesse McKenzie from the Royal Society of New Zealand and the Primary Science Teacher Fellows will be linked to the Primary website. The Science Fellows are charged with outreach to schools when they complete their Fellowship. When these Fellows return to school they bring with them a source of information, energy, passion and mana. As part of this outreach, the activities developed will be included on the website so that more schools may benefit from their experiences.

The Primary Committee sees its role as being a source of support to primary and intermediate teachers. There are some local science associations that have a great deal to offer the primary and intermediate community, but unfortunately there are some areas that have very little on offer. Through a common portal it is hoped that this Committee is able to link teachers and associations with more experience to those who need more help and support.

For further information contact: steven.sexton@otago.ac.nz

than 21, so it will be a matter of selecting what you want from these sorts of possibilities.

As with any good course planning we have started with the key concepts we believe should be in this course. Human Biology is centred around an understanding of the systems of the human body, but that is not all there is to it.

To some extent, the content of the course will depend on whether or not these students are also taking a general science course. Students will need some understanding of genetics if they are to continue in Biology to Level 2, so if they are not doing a science course as well, this topic will need to be included in their Human Biology course.

So where to at Level 2?

It should be quite feasible to develop a course at Level 2 with a strong Human Biology flavour. Once again the realigned standards, particularly the internals, have been developed to provide a degree of context flexibility.

For example, students might build on their Level 1 Life Processes knowledge by studying human metabolism in more detail, focusing on cell specialisation in various human tissues, and exploring human physiology (structure and function) in relation to our niche. Ecology and Evolution AOs at Level 7 could well be applied to human contexts such as an exploration of Pacific Migration patterns and the evidence on which our latest understandings of Maori and Polynesian origins is based. Teachers might also consider including achievement objectives from the Health and Physical Education learning area, or from Social Sciences in order to meet the needs and interests of their students.

Assessing a Level 2 Human Biology course may involve using 13 credits of internal Biology standards (all internals except Bio 2.6 Community patterns). All three external Biology standards have potential for a Human Bio course, depending on the interests and Level 1 background of the students involved.

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advancing primary science

By Richard Meylan

Exposing students to quality science experiences at primary school is vital. It is vital because this is when students’ enduring attitudes to science develop. If these attitudes are negative then it is unlikely they will continue on with science education, so cutting them out of a wide range of careers as well as an understanding of the complex world they will be living in. Addressing the need to develop positive attitudes to science is the driver behind The Royal Society of New Zealand’s (RSNZ) commitment to Advancing Primary Science.

The trigger for this initiative came from the 2006 Programme for International Assessment (PISA) results. In this assessment of the scientific literacy of 15 year olds from fifty-seven countries, only two countries performed better than New Zealand.

As well as assessing scientific literacy, PISA also gave students a questionnaire on engagement and motivation.

Interestingly, results from this showed that New Zealand students were less likely to be interested in science and to believe they are good at science than their cohorts in other OECD countries. On other engagement and motivation measures New Zealand students were often only around the OECD average. This was reinforced in the Trends in International Mathematics and Science Study where New Zealand’s Year 9 students tended to be more reticent than their international peers on the value of science.

The PISA results highlighted a New Zealand dilemma; our secondary students are capable in science but have a less than enthusiastic attitude to the subject.

So when do students develop their attitudes to science? The RSNZ commissioned the New Zealand Council of Education Research to review the research on this. It concluded that the evidence strongly supports that Years 7 and 8 are a time when attitudes to ongoing science learning are likely to consolidate.

So what are our primary students doing at this important stage in developing attitudes to science? In 2006, students were spending on average 45 hours a year on science, which is a decline on the 66 hours they were spending in 2002. With the present emphasis on numeracy and literacy this is unlikely to have improved in 2010. The National Education Monitoring Project 2007 (NEMP) found that at Year 8 the percentage of students ‘particularly enjoying science’ at school dropped from 37% in 1999 to 24% in 2007 and, concerningly, the percentage with a negative view increased from 15% in 1999 to 37% in 2007.

In an attempt to identify why this happened the RSNZ organised a meeting of those concerned about primary science. From this it was agreed that there was a need to raise the profile of science in the school teaching

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programme and to address teachers’ lack of confidence in tackling it. There was a real need to ‘nudge back the pendulum’ and the RSNZ could play a useful role in acting as a catalyst for this.

The first action for Advancing Primary Science was to ensure there was support from key players. NZASE was already driving change through their Primary Science Committee and organisations such as the School Trustees Association, the NZEI, and the New Zealand Principals’ Federation all agreed it was an important initiative.

Presentations were made to Primary Principal clusters who, though acknowledging their role in raising the profile of science, wanted to know what practical ways the RSNZ could help their teachers.

This was the impetus for the Primary Science Teacher Fellowships. Supported by the Ministry of Research, Science and Technology this scheme allows up to 30 primary teachers a year to come out of the classroom and work alongside scientists for six months. The scientists have been very supportive and have enthusiastically incorporated primary science teachers into their research programmes, offering them a wide range of experiences so they get a good understanding of the nature of science.

The criteria for becoming a Primary Science Teacher Fellow includes a desire to improve their knowledge of, or confidence in, science, agreement to take a leadership role in their school after the Fellowship, and the Principal’s commitment to supporting this leadership role when they returned to the school.

The Teacher Fellows have also been important catalysts in creating regional networks under the auspices of NZASE. These networks have been involved in creating the environment to support primary teachers who lack confidence in teaching science. They have had considerable success in regions such as Wellington. Here, using personal invitations and ensuring teachers are involved in activities they can use in the classroom, after school sessions on primary science have been well attended.

NZASE regional associations are now looking to support regional workshops with the intention of bringing together all the parties in their community who are supportive of primary science to ensure there is a co-ordinated approach to raising the profile of science in primary schools.

These actions are now starting to nudge back the pendulum to science in primary schools, thanks to the efforts of a wide range of people and organisations working in a co-ordinated way.

For further information contact: Richard.Meylan@royalsociety.org.nz

With 2011 being the International Year of Chemistry (IYC 2011), it is time to start thinking about how to integrate some of the aims of this celebratory year into our teaching programmes. The theme of the year is “CHEMISTRY – OUR LIFE, OUR FUTURE” and is an opportunity to celebrate the achievements of chemistry and its contributions to the well-being of humankind. It will promote the message that all known matter is composed of chemical elements – or of the compounds made from those elements – and that our understanding of the chemical nature of the world is grounded in our knowledge of chemistry. It is a great chance to tell the story of chemistry: from the discoveries and inventions that have improved our lives, to exciting opportunities on the horizon. IYC 2011 events both internationally and locally will particularly emphasise that chemistry is a creative science essential for sustainability and improvements to our way of life.

International events for school children include a Global Experiment where students around the world will be invited to explore one of Earth’s critical resources: water. Students from primary schools to high schools will be invited to report their findings on water quality and water treatment on an online map, allowing them to compare results and connect with other students around the world. Currently, there are four planned activities designed to cover chemical concepts such as acidity, salinity, filtration and solar still water purification. For further information go to:http:// tinyurl.com/253sevj.

Another international competition can be found at: www.scienceacross.org – a competition to design a national stamp. It would be great to have a New Zealand contribution to this event.

Also available on the Science Across the World website are some programs that provide useful starting points for students to think about chemistry. Particularly, “Chemistry in our Lives” provides opportunities for students to find out more about the chemical products that people use in their homes.

In Canada, an international event to design a periodic table is being organised. Students from around the world are invited to join together to create an innovative and

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imaginative periodic table that combines art and science.

Classes can register (www.chem13news.uwaterloo.ca) for one element tile (15cm × 15cm). The resulting periodic table will be available on an interactive website.Perhaps this is something that could be duplicated in schools, thus providing a link between art and science classes.

Visit: http://www.chemistry2011.org/ to find out more about the international aspects of this programme.

Information will be available later in the year about NZ events planned for IYC 2011.

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HAVE YOU SEEN THESE? Ever Wondered?A Local TV series Ever Wondered? is a 10-part TV series that takes a celebratory look at the cutting edge scientific research being performed in New Zealand. Each week is dedicated to a particular topic such as astronomy, functional foods, sports science and technology in medicine. Sponsored by the Royal Society of New Zealand, the series is part of TVNZ 7’s Spotlight on Science and Technology Month in August, which is partnered by the Ministry of Research, Science and Technology. The sponsors’ aim is to bridge the gap between the world-leading scientific research being performed locally and the interested public. The host, Dr John Watt, from the School of Chemical and Physical Sciences at Victoria University, is the MacDiarmid Young Scientist of the Year and winner of the Prime Minister’s MacDiarmid Emerging Scientist Prize. Episodes can be viewed at TVNZ 7 website (http://tvnz.co.nz/tvnz-7).

Chemistry – A Volatile History Another series worth a look is from the BBC - “Chemistry – A Volatile History” found at: http://tinyurl.com/29oy2yv.

This three-part series focuses on the story of how the elements were discovered and mapped. It traces the history of chemistry from the alchemists to the modern day. Each episode is only 10 minutes long and emphasises the place of the elements in our everyday lives, as well as documenting the work of key players in the discovery of the elements and some of the fundamental ideas of chemistry.

For further information contact: Suzanne.Boniface@vuw.ac.nz

The 42nd International Chemistry Olympiad Competition This year, the 42nd International Chemistry Olympiad Competition was held in Tokyo, Japan, from 19–28 July. It was attended by 68 countries and 269 students. The New Zealand team consisted of Stuart Alexander (Christchurch Boys’ High School), David Bellamy (Christ’s College), Jai Min Choi (Massey High School) and Luke Xu (Massey High School) and was accompanied by Dr Owen Curnow (University of Canterbury) and Dr Duncan McGillivray (University of Auckland). The opening ceremony was attended by His Imperial Highness, Prince Akishino and his wife Princess Akishino. The weather during our stay was typically 35°C and very humid, and came at the end of their longest recorded period of tropical heat. The five-hour laboratory exam took place on Thursday, 22 July and the five-hour theoretical exam took place on Saturday, 24 July.

All of the New Zealand students attained bronze medals,

with Stuart Alexander having the highest bronze medal in the Competition.

New Zealand Olympiad team (L to R): David Bellamy, Luke Xu, Jai Min Choi, Stewart Alexander.

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complex investigations for Level 5

By Paul King The ‘Nature of Science’ section of the NZ Science Curriculum demands that students “Develop and carry out more complex investigations…” (Level 5 Science).

The challenge for science departments is to prepare a whole range of suitable investigations that will meet the curriculum requirements, interest the students, enthuse the staff and be cheap.

Here are a couple to consider adding to your repertoire.

The simple potato cannon Exhausted felt tip pens and markers provide an endless source of short stiff plastic tubes.

1. Plug one end of such a tube with raw potato (or carrot or apple…this could be a separate investigation). This is the bullet. The length of the bullet might be important; it can be measured from the length of the hole in the potato.

2. Then the simple clever bit (I wish I had thought of ) is to make an airtight piston at the other end of the tube by forcing in another plug of potato. Use a long pencil as a piston rod to shove the piston (quickly) along the tube.

3. As the potato piston is pushed up the tube the compressing air exerts forces on both the piston and the bullet. When the compression force is greater than the maximum static friction force between the bullet and the tube the bullet will accelerate out of the tube with a distinct ‘pop’. The maximum range (so far) is of the order of 5m.

4. The investigating groups are to find the set of conditions that will produce the greatest range for the projectile. The list of variables they will need to consider might include: (1) The angle of firing; (2) The height above ground when firing; (3) Speed of the piston push; (4) Length of the piston; (5) Length of the cannon; (6) Length of the bullet. And…no doubt there will be others!

Comment There are a lot of variables, which meets the requirements for Level 5 investigation, but in this case they are all quite easy to control. The conditions for maximum range will only become evident with the clear reporting of the accurate data gathering. All of the Nature of Science boxes are being ticked.

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Apart from a bit of mess there are no downsides to this investigation. Safe, realistic and fun. Just a little care should be taken with the hand holding the pencil. It can run into the end of the cannon tube quite hard. I quickly learnt to avoid this (used a longer pencil) but wearing a ski glove to give some padding protection might be in order.

The drinking straw rocket Even more simple than the potato cannon but with the possibility of more elaboration. The students can be asked to construct the device.

The tubes don’t have to be straws, various felt tip and marker tubes work fine, but straws can have their length altered easily with a pair of scissors and they fly further.

The objective once more is to investigate the conditions needed to achieve maximum range, but new variables need to be taken into account.

For example: • what is the best volume of bottle to use?

• what is the best length of rocket straw?

• should the straw be weighted at the tip?

• how can the squeeze force be kept constant?

(Answer – do your best! Have just the one squeezer in a group who always squeezes just as hard as they can. It will produce very consistent results.)

• what is the effect of taping tiny flights to the end of the “rocket”?

• I wonder what else the students will come up with?

The real prize of this kind of activity is the ignition of invention, but that is not in the achievement objectives.

For further information contact: dhousden@xtra.co.nz

By Jenny Pollock, SCIPEC Standing Committee The four Planet Earth and Beyond (PEB) standards at Level 1 NCEA are derived from the PEB strand at Level 6 of the NZC. Each standard is worth 4 credits and is internally assessed.

They can be assessed by written reports, posters, or Powerpoint presentations. Standards 1.13, 1.14 and 1.15 could also be assessed by a formal test, although this is not recommended. The assessments can be done in stages if need be, and evidence accumulated and collected in portfolios.

At Levels 7 and 8 the Planet Earth and Beyond strand has become a new subject called Earth and Space Science (ESS).

Students do not need Level 1 PEB standards to take Levels 2 and 3 ESS, although courses assessed by these standards would give valuable background.

Science 1.13: Demonstrate understanding of the formation of surface features in New Zealand This standard requires the student to describe the formation of surface features in New Zealand by linking external and internal geological processes.

Surface features can be one or more local or national landforms. External geological processes involve erosion and weathering as caused by wind, ice, water, animal and plant action and sea level changes. Internal processes involve familiar tectonic processes such as the formation of volcanoes or mountains, lateral movement along the Alpine Fault, and movement along fault lines.

The surface features to be studied and assessed can be chosen from any local or national features of interest such as volcanoes, caves, sand dunes, mountain ranges, and fault lines. A field trip to the area of interest can also form part of the assessment.

Possible contexts are: • changes in the Manawatu River level and the formation of adjacent river terraces • the effects of sand particle size, wind speed, water currents, and vegetation on sand dune movement • the relationship between the line of volcanoes from Ruapehu to White Island, and the subduction of the Pacific plate under the Australian plate • the events that produced the layers exposed in a road cutting • how Farewell Spit formed • how Banks Peninsula or Otago Peninsula formed • limestone formations such as caves, sink holes • sand dunes and dune lakes • landslides • glacial features and valleys • fiords, drowned river valleys • mountain ranges such as the Southern Alps, Kaikoura Mountains, Tararua Ranges • the Alpine Fault and other major fault lines.

Science 1.14: Demonstrate understanding of carbon cycling Carbon is an important part of many molecules that make up organic and inorganic matter. This standard requires the student to understand how the addition, removal and storage of carbon cycle this essential element.

Carbon is added to the atmosphere as carbon dioxide and methane by respiration, excretion, decay, combustion

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and volcanic activity. Carbon is removed from the atmosphere by photosynthesis and by dissolving in water, especially the oceans.

The atmosphere and ocean dynamically pass carbon between them, and cold water absorbs more carbon as carbon dioxide than warm water.

Carbon is stored in reservoirs. Short-term, carbon is stored in forests and phytoplankton, and long-term, it is stored in sediments, limestone, fossil fuels and other rocks. The process of subduction results in carbon rich metamorphic and igneous rocks.

Together these three processes ensure that carbon is continuously cycled throughout the atmosphere, oceans, rocks and all life.

Possible elaborations are: • visits to farms to observe breathing, eating and excreting animals • visit, or see DVDs of, coal mines, oil drilling, or natural gas extraction • visit, or see in pictures, limestone outcrops such as the Pancake rocks or the limestone formations in Oamaru • witness, or see in pictures of, a stormy day at sea, because the water agitation increases the amount of carbon dioxide dissolved • look at pictures of phytoplankton with their shells formed from calcium carbonate • learn about subduction of sediments and rocks, the subsequent formation of magma and the eruption of volcanoes resulting in carbon dioxide being returned to the atmosphere.

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Level 1 PEB achievement standards

science teacher

Science 1.15: Demonstrate understanding of the effect on planet Earth of astronomical cycles This standard requires the student to understand how astronomical cycles directly affect different parts of the Earth’s surface. The astronomical cycles are the familiar ones of the spin of the Earth, the orbit of the Earth around the Sun and the Moon around the Earth, plus the effect of the Earth’s tilt and the heating effect of the Sun. These cycles result in day and night, seasons, phases of the Moon and tides. They also result in changes of temperature according to time of day, latitude, and season. The heating effect of the Sun directly affects the formation and direction of winds and surface ocean currents. Models, animations and other diagrammatic representations should be used to aid understanding of these cycles and their effects.

This standard would suit a range of tasks with evidence accumulated and collected in a portfolio.

Possible assessment tasks are: • observations of the differing lengths of day and night during the year • the area of a sphere illuminated at different tilt angles from a light source • measurements of how the angle of the Sun affects the amount of heat hitting the same surface, according to time of day and year • making a sundial to track the Sun’s movement and height during the year

continued on page 48

New Zealand Association of Science Educators

47

NZ

science teacher

science/PEB

technicians

125

this week’s challenge is...

By Robyn Eden, ScienceTechnician, Queen Margaret College In 2009, the Science Department introduced a new unit in Year 10 called Vulcanology. This was the next step along the path of the Geology unit taught to our Year 7 students. The teacher in charge wanted an experiment which developed the investigation, planning, data processing and evaluation skills of the students in preparation for Year 11 Science. Her suggestion was that the students look at lava flow using the viscosity of substances representing different types of lava.

“Hey Robyn, I want to do an experiment showing lava flow/ viscosity using, I guess, something like porridge or golden syrup, but I want different flow rates.”

“What distance do you want to run it over? What sort of volume are you looking at? Do you want to run a marble through the liquid or does the liquid itself move?”

“We should make it so we end up with a resource that can be used for other experiments as well. Metre-long lengths would be useful − we could use that length for all sorts of things − let’s go with that. What will we use?”

Time to see what could be useful. Trunking looks a good idea and could work, but what size?

“Only comes in 3 metre lengths − could you cut it so I could get it in my car?”

“Sorry lady, bring a hacksaw.”

Once the trunking had been collected and cut into lengths − thanks to the brilliant caretaker − it was time to start getting it all to work.

It was decided that golden syrup would be used, so time to try to do some trials. It all sounds very simple − should be a breeze! Retort stand and clamp to hold the trunking, golden syrup ready, spoon ready, stopwatch ready − problem: the trunking needs to be level before the liquid is added. Try an ice cream container to balance the trunking on − that works; give it a flick when the stopwatch is started and all systems go. A minute later and the golden syrup has moved 3cm. That’s good, but I need a mark to show where I started from. Add marker pen to the list. Dilute the golden syrup because I am onto a winner here. Ooops, the 50% golden syrup is off the end in less than a second. Consultation time again, and it was decided that the viscosity of different fluids would be tested. Glycerine might work; detergent, worth a shot. What about liquid honey; engine oil could be

good? There is nothing like standing in the supermarket isle turning bottles of liquid honey over to see how they flow!

After many trials, it was suggested that golden syrup, neat detergent, diluted detergent (66%) and glycerine could be used. The volume used was to be the amount held by a plastic teaspoon, as the volume used didn’t appear to make any difference to the flow rate. The height was the height of an ice cream container.

The students were required to plan an experiment to test lava flow, but for the actual experiment, the students were given the method we devised. They were required to test the viscosity of four substances.

The students worked through the practical systematically and enjoyed doing it. They obtained good data and interpreted the data well. Job well done!

While we were working on this experiment, it showed us that what seemed to be a simple idea can, in fact, be more complicated. We were surprised that many of the substances we thought would be ideal were, in fact, not suitable.

When a teacher comes to the technician with an idea for a new experiment, it can take a while to work through what is required. When making the request, it is important to remember that we all visualise things differently, and getting the idea across can sometimes be a bit difficult, but constant communication is the key. Diagrams are a useful starting point. It is important that the technician is able to talk to the teacher at each stage so any problems that arise can be dealt with promptly. The technician will also be trying to develop this new resource in between the other needs of the department, so it will often take longer that the teacher may like. Of course, not all suggestions for experiments work, but teachers can be assured that the technician will have done everything they can to try to get it to work. It is also important to realise that the key to developing new resources is good communication and patience.

For further information contact: BeMcKinnell@papatoetoehigh.school.nz

continued from science/PEB page 47 • time variations in published tide tables and their relationship to the Moon’s orbit • observations of the phases of the Moon.

Science 1.16: Investigate an astronomical or Earth science event This standard is assessing investigating in the widest sense. Assessments may consist of practical investigations, field trips, research, or a combination of these. Scientific evidence can be primary or secondary, and collected from a variety of sources such as direct observations, collection of experimental and/or field data, resource sheets, photos, videos, websites and reference texts. An astronomical event can be selected from an historical or recent event, discovery or space probe exploration. An Earth science event can be selected from an historical or recent event taken from

48 New Zealand Association of Science Educators

geological science, marine science or atmospheric science, or a combination of these.

Possible contexts are: • Shoemaker-Levy Comet hitting Jupiter • erosion of a beach • tracking a planet such as Venus across the night sky and recording retrograde motion • dust storms on Mars • finding water on Mars • extreme weather such as storms, cyclones • extreme tectonic events such as earthquakes, tsunamis and volcanic eruptions • effect of storm waves and surges on a coastline • effect of weak acid on marine creatures.

For further information contact: jenny.pollock@xtra.co.nz

EARTH AND SPACE SCIENCE BIENNIAL FIELD TRIP 2011 From Mt John Observatory in Tekapo to Kaikoura If you are interested contact jenny.pollock@xtra.co.nz

NZASE National Primary Science Week 2nd – 7th May, 2011

The NZASE National Primary Science Week is a new initiative that has been developed to replace the very successful biennial Primary Science conferences.

The two main aims of the NZASE National Primary Science Week are: • to continue to support teachers of primary science and so enhance teaching and learning of science in the primary school through professional development and • to celebrate science throughout New Zealand Primary Schools by involving students, teachers, parents, communities and science providers in a variety of fun, engaging science activities.

The NZASE National Primary Science Week will be coordinated by the Primary Science Standing Committee of NZASE. The event will happen simultaneously in 7 regional centres across NZ; Auckland, Bay of Plenty, Wellington, Nelson, Christchurch, Dunedin and the West Coast.

For further information please contact: Chris Astall (National Coordinator) at chris.astall@canterbury.ac.nz or Jessie McKenzie at jessie.mckenzie@royalsociety.org.nz

Craig Steed - Convenor, Email: SteedC@freyberg.ac.nz

National NZIP Conference

CONSTANZ ‘11

The 15th National NZ Institute of Physics Conference

The Science Technicians’ Association of NZ Conference 2011

17-19 October 2011

10 to 12 October 2011

Victoria University, Wellington Energise your physics teaching with three days of ideas, stimulation and interactions!

For further details visit: www.nzip.org.nz

John McGlashan College, Dunedin This Conference will appeal to all school science technicians, and also some technicians from tertiary institutions (such as Polytechnics) For further information contact: Margaret Woodford - Conference Convenor, Margaret.Woodford@kvc.school.nz or

CONSTANZ ‘11 Anne-Marie Pulham - Secretary, ampulham@kavanagh.school.nz

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