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science teacher 2009

Featuring: Carbon Discovering nanotubes Making carbon footballs Soils are carbon sinks Measuring carbon stocks Carbon in the stars Carbon emissions from building construction Predicting climate change Science teaching and the NZ Curriculum And more ...

Number 120

ISSN 0110-7801


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Mailing Address: NZASE PO Box 1254 Nelson 7040 Tel: 03 546 6022 Fax: 03 546 6020 email:nzase@confer.co.nz

Editorial 2 From the president’s desk 3

Editorial Address: lyn.nikoloff@xtra.co.nz Editorial Board: Barbara Benson, Suzanne Boniface, Beverley Cooper, Mavis Haigh, Rosemary Hipkins, Chris Joyce. 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 NZASE Subscriptions (2009) School description Secondary school Intermediate, middle and composite schools Primary/contributing schools

Roll numbers > 500 < 500 > 600 150-599 < 150 > 150 < 150

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Subscription includes membership and one copy of NZST per issue (i.e. three copies a year), and extra copies may be purchased for $9.00 per issue or $25 per year (3 issues). 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 121 - Sound 20 April (publication date 1 June) Issue 122 - Light 20 August (publication date 1 October) 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.

contents

contents Feature: Carbon Who discovered carbon nanotubes? 4 Making carbon footballs from scratch 7 Sustainable steel construction and embodied CO2 assessment 10 Carbon in soils 13 Measuring carbon stocks 16 Carbon cycle: developing global and regional understanding 19 Terrestrial ecosystems – carbon sources or sinks? 22 Carbon in the stars 26 Regular features Science education: Science and the NZ curriculum 29 Time to bring science alive 32 Implementing the new curriculum 34 History Philosophy of Science: Is Matauranga Maori science? 36 Just for starters ... Food microbiology and food safety 39 Resources: National Library 40 Visual soil assessment 41 Ethical guidelines 42 Ask-a-scientist 38, 42 Science News 12, 40 Subject Associations: Biology 43 Primary Science 44 Physics 45 Chemistry 46 Science/PEB 47 Technicians 48

Measuring carbon exchange at Okarito Forest, South Westland. Photograph courtesy of John Byers

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sustainability and innovation I have been following avidly the economic crisis and the election/inauguration of the USA President, Barack Obama. For me, the two are interlinked – they bring to an end arrogant governance by economists/bankers and other self-proclaimed experts, replaced (I hope) by responsible, sustainable stewardship of the Earth’s valuable resources. It seems that Barack Obama will support measures to mitigate global warming. Now one of the world’s most powerful economies is finally moving towards a sustainable future. So be assured that sustainability is the new/old buzzword that you will be hearing a lot more about. So what has this got to do with the NZST, you, science and teaching? A lot! As teachers you can no longer work in an isolated bubble of text books and educational idealism – your students are future stewards of this planet and its resources have to be managed sustainably. They, and therefore you, are going to have to become familiar with sustainability – not as a philosophy but what it means for our economy and businesses and how it will impact on all of our activities and expectations of personal wealth. So how much do you know about our economy? Last year, I was at a conference for the quality fraternity, and the opening speaker was CEO of Business NZ, Phil O’Reilly. He gave a very challenging address pointing out that New Zealanders need to be mindful that our economy is only the same size as that of Sydney. We have to do things differently...innovatively. “I argue that one of the things we need to do brilliantly better than the next guy is innovation...it’s rather depressing that innovation is not at the forefront of our thinking in NZ, yet innovation is actually quite important...,” explains Phil. Innovation has, over the years appeared, to my knowledge, in various forms in curriculum documents – usually under the guise of technology. It is almost impossible to teach innovation skills. Innovation usually results from a need. However, teachers can inspire students to move into careers where their skills may one day lead to innovation. This can be done in part, by informing them about innovative New Zealanders, especially our scientists and engineers. This issue of the NZST features a plethora of scientists and engineers working in the area of carbon. They are as follows: Have you ever wondered who discovered carbon nanotubes? John Abrahamson at the University of Canterbury. His article (page 4) makes compelling reading for all teachers. But pushing the scientific boundaries does not always bring success as he writes: ‘Timing is everything when it comes to discovery, and not always the earliest discovery is recognized.’ Douglas Russell and his team at the University of Auckland (page 7) are trying to identify the pathway by which Polycyclic Aromatic Hydrocarbons (or PAHs) are formed because they are ‘...extremely hazardous, being linked with cancer and mutations...’ We all stand to benefit from his work. If we are to mitigate the impact of global warming by reducing the amount of greenhouse gases, we have

to better understand its sources and sinks. ‘Refining our understanding of the carbon cycle is an important stepping stone to improving prediction of future climate change’, writes Drs. Mike Harvey and Sara Mikaloff-Fletcher, National Institute of Water and Atmospheric Research (page 19). And there is no better place to look than our soils - ‘Soils store substantial amounts of carbon in soil organic matter, and the amounts are an important component in the global carbon cycle,’ write Graham Sparling and Louis Schipper (University of Waikato) (page 13). How do you measure carbon stocks in New Zealand’s forests, shrublands and soils? Ian Payton (Landcare Research) takes readers on a short walk through part of the climate change labyrinth (page 16). Also working in the field measuring carbon stocks is David Whitehouse and his Landcare Research team (page 22), and his work is also featured on the front cover of this issue. Where does carbon come from? Clare Worley, Mita Brierley and Karen Pollard, (all from the University of Canterbury) give some stellar insights (page 26). I have been told, I may be wrong, that almost half of the world’s annual concrete production is used in China’s construction boom! Yet concrete is not recyclable, so what are the implications for global warming and therefore sustainability? Steel construction is the most sustainable method, explains Clark Hyland (Steel Construction NZ Inc.) (page 10). However, this issue is not all about science. Teaching this year will be dominated by the new NZ Curriculum and I strongly advise you all to read Miles Barker’s article (page 29), and for primary teachers Ian Milne’s (page 32) and HODs’ Graham Foster’s (page 34). In our History, Philosophy of Science section we feature the first of three articles written by Philip Catton (University of Canterbury) about Mataurangi Maori and science (page 36). So, along with all your regular features, this issue is a must read for science educationists. Back to the world’s economic crisis - books will be written about these times, fortunes and reputations will have been made and lost, careers will have been forged for those who found innovative solutions, and some people will be winners and others losers. For those who win – they were simply the right people at the right time – a serendipitous moment. While you can’t teach innovation or serendipity, you can prepare the mind which fortune favours. So make sure your classroom this year has one foot in the real world – the world of sustainable business – and one foot in the ground preparing the fertile mind. I hope the authors in this journal inspire you, in turn, to inspire your students to journey further into the world of science and engineering. In a world that is constrained by resources, we here in NZ, as Phil O’Reilly insists, have to do things differently, innovatively. This issue highlights how some of our scientific and engineering fraternity are doing just that – they are indeed beacons in the stormy seas of the current global crisis. Kind regards Lyn Nikoloff Editor


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Last year, 2008, was a busy one for NZASE. Bev Cooper’s time as Senior Vice President ended, and we welcomed Lindsay Conner as the new Junior Vice President. Inevitably, we were still feeling the effects of Peter Spratt’s untimely death. This has led to major changes within the organisation, and an ongoing evaluation of the role the Executive and Council can play in the future. Firstly, we needed to change how our administration was being done. Many thanks to Beverley Booker and the Royal Society (RSNZ) for their role in managing the day to day running of NZASE for the past few years. We have now contracted Conferences and Events, a Nelson and Wellington based firm, to take over this role. They have been streamlining a lot of our core work; please visit our website to see this. Registration for the membership of NZASE, and access to the Certificate of Science and NZIP resources, can now be done online and we urge members to use this facility. We are also slowly making the website even more userfriendly. Thanks to Andy Kent for his hard work. Secondly, we are considering the role of NZASE for the future. Members at the last AGM decided that we had a wide role to play; the challenge now is defining and implementing this. We especially need to make sure that we maintain an educational overview because that is our core business. I see these as our challenges for 2009. These changes have not meant that our links with the Royal Society have gone. We are still an affiliated society of the RSNZ and have regular meetings with Richard Meylan, Jessie McKenzie and more recently Joanna Leaman have ensured continuity with this organisation during the inevitable changes. Several of the standing committees, for example Primary Science led by Ian Milne, also have strong links with the Royal Society. This is a very effective relationship that is

tackling the issues highlighted in several recently published reports. The main point of these is that New Zealand students are not doing as well as they could in Science; this should be of concern to us all. It was good to see many of you at the meetings held around the country to consult on the Curriculum and NCEA alignment. This project has been very difficult at times, especially with the narrow parameters set by the relevant government agencies, which did not into take account our very diverse sector. Thank you for the feedback that many of you have given us, it has been very useful. We have always welcomed robust debate and the many thoughtful comments in the feedback have been appreciated. By the time this journal comes out hopefully new matrices will have been put onto the web for further consultation. And hopefully the new matrices, especially at Level One, will be able to meet a wider range of needs. There are still many challenges to face however, such as making sure that the specialist sciences have a good range of standards, catering for the needs of less able students, and designing standards that give effective coverage of the Planet and Earth Strand. And above all, NZASE needs to work hard to ensure that any changes are well resourced. The changed timelines for implementation will help this. Finally, I wish a Happy New Year to you all. I hope that the year has started well. Don’t forget the wide range of conferences during the year, for teachers of Primary Science, Physics, Chemistry, Biology and for the Science Technicians. Look for information or links to these on our website. A lot of hard work has been going into these, so make sure that you get your registration in early. Jenny Pollock President

fromthepresident’sdesk

looking forward

NZASE directory National Executive

Standing committees

President: Jenny Pollock, Nelson College for Girls jenny.pollock@xtra.co.nz Tel: 03 5483070 or 021 129 3174

Biology: Chemistry: Physics: Primary Science: PEB/Science: Technicians:

Junior Vice President: Lindsey Conner, School of Sciences and Physical Education College of Education, University of Canterbury lindsey.conner@canterbury.ac.nz Treasurer: Carolyn Haslam, The Faculty of Education, The University of Auckland, Private Bag 92601, Symonds St Auckland c.haslam@auckland.ac.nz Administrator: NZASE administrators nzase@confer.co.nz Tel.: 03 546 6022

Jacquie Bay j.bay@auckland.ac.nz Suzanne Boniface Suzanne.Boniface@vuw.ac.nz Dave Housden dhousden@xtra.co.nz Ian Milne i.milne@auckland.ac.nz Jenny Pollock jenny.pollock@xtra.co.nz Margaret Garnett mgarnett@christcollege.com

RegionalAssociations For contact details for regional associations visit: http://www.nzase.org.nz/regionalassociations.html




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who discovered carbon nanotubes? Timing is everything when it comes to discovery, and not always the earliest discovery is recognized, as John Abrahamson, Chemical and Process Engineering, University of Canterbury, explains: Buckyballs and nanotubes Nanotechnology and especially carbon nanotubes are hot topics in the scientific world. Yet just 20 years ago this area did not catch the scientific imagination. Our history of nanotubes at Canterbury University shows that discoveries when they happen will not necessarily lead to widespread recognition and excitement; this also depends on whether people are sensitized to the general area – what could be the outcome of the discovery? Also, it reinforces a general thought that much work leading to significant advances is not funded for that purpose, and often the advance comes from an unplanned observation. In this case, our discovery of carbon nanotubes at Canterbury University in the 1970s occurred before the C60 spherical molecule was found in 1984 (it was called a ‘fullerine,’ or ‘buckyball’ after Buckminster Fuller, the architect whose geodesic buildings resembled C60 on a human scale). This ‘molecular football’ with diameter 0.7nm (7 Angstroms) certainly captured the imagination of many people including many non-scientists, and stimulated a whole wave of ‘nano’ chemistry. (Figure 1 buckyball and nanotube). For the first time, an easily pictured entity with a simply defined chemistry had been found that is much larger than a simple molecule (in the range of nanometres in all directions, rather than fractions of a nanometre). It helped that the ball could be seen by the electron microscopes of the time. And it was just a small step to thinking about an extended version of the buckyball – one which was stretched out far in one direction. This mental preparation seems to have led to an immediate recognition of the stretched version in 1991, when Sumio Iijima from Japan published a description in Nature. His carpet rolls of graphitic carbon (or nanoscale chicken wire) were quickly called ‘carbon nanotubes,’ or just ‘nanotubes.’ The amazing properties of carbon nanotubes were rapidly uncovered, some related to the strength of the aromatic layers, and some to the length compared with their diameter. They were obviously much more useful than buckyballs. Nanotubes are the strongest material known, and one can make transistors of them, and cool small electron sources for all manner of uses, such as computer displays and X-ray generation. The number of research publications on nanotubes is now about 200 per week and fast increasing!

Carbon arcs for acetylene and temperature standards



We now know that there are several ways of making carbon nanotubes, and in 1977 we serendipitously used an electric arc struck between carbon electrodes. In the early 19th century an arc between carbon electrodes began the study of electrical gas discharges (Humphrey

Davy demonstrated such a ‘carbon arc’ as a new light source in London in 1810), and in the 20th century it has been useful for cinema projectors and searchlights. In our work in the 1970s, we certainly did not set out to find carbon nanotubes, but incidentally saw them because we were using such an arc to react carbon with hydrogen. Our purpose was to process coal to make acetylene, a chemically reactive gas that can react with hydrogen chloride to make vinyl plastics. We converted the carbon arc into a chemical reactor by closing it off from the air in a metal vessel, to chemically react carbon with hydrogen. As part of this exercise, we needed to understand where the energy dissipated in the arc was flowing, and so we wanted to measure the temperature of the electrodes. This needed to be done from a distance (optically with a ‘pyrometer’) as no known contact thermometer could survive the high temperatures. How to calibrate our pyrometer to make sure of our measurements? If the current of a carbon arc is controlled to a low value (10 to 20 A) the arc spreads out evenly on the positive electrode, and the surface reaches a high brightness temperature reproducible from lab to lab with only 5 K variation. This brightness temperature is 3800 K when operated at atmospheric pressure. Thus this low current arc is considered a useful secondary temperature standard. We used this standard for calibrating our pyrometer. However, we could not understand why the specific temperature of 3800 K was reached, because the simple interpretation was that the graphite would be in equilibrium with its carbon vapour, and the best estimate of the equilibrium temperature (the sublimation temperature at one atmosphere) was considerably higher at 3950 K. To explain the discrepancy, we suggested (Abrahamson 1977) that part of the evaporating carbon electrode was released as tiny carbon particles, and that a cloud of these were suspended in front of the electrode. Our pyrometer measuring the radiation then saw this cloud rather than the electrode itself. Because the particles were so small (several nm) a large fraction of their carbon was at the surface and so had higher energy than ordinary bulk carbon. This was expected to move their equilibrium temperature with carbon vapour down by several hundred K, explaining the discrepancy. Happy with this explanation, we were after this, thinking of small particles.

Nanotubes at the University of Canterbury Everyone using the standard carbon arc had operated it in air, using up electrodes quite rapidly because of their oxidation. We did not have the funds to buy electrodes so frequently, and instead we flooded the arc space with nitrogen to exclude the oxygen. The measured operating temperatures did not change, but after operation and cool-down, on removing the electrodes my PhD student Peter Wiles noticed a rainbow-type colour (a ‘birefringence’) on the positive electrode tip. This indicated a very fine structure in line with our explanation above, and on examining the surface with an electron microscope, we were surprised and


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carbon b

a

a

Figure 1: Wire models of (a - left) a buckyball C60 molecule. (b - above) a single-walled carbon nanotube. b

Figure 2: Electronmicroscope images from our 1978 paper. (a) TEM of carbon crystallites held on carbon nanotubes found on the positive electrode of a carbon arc. delighted to see nanoparticles there (small enough to (b) SEM of the network of carbon nanotubes found on the electrode. explain the temperature difference, but not yet called ‘nanoparticles!’). They were still in place above the surface of the cooled electrode tip because they were stuck to a ‘carbon grass’ – a forest of tiny carbon fibrils. These were later to be known as nanotubes. We considered the carbon fibrils as part of our successful higher energy carbon explanation for the lower-thanexpected temperature and first focused on this aspect. We published this (Wiles & Abrahamson 1978) complete with scanning and transmission electron microscope (SEM, TEM) images (see Figure 2). Having done that, we got the help of our local materials specialist Brian Rhoades (Canterbury University) to help us decipher the structure of the fibrils. We used the electron beam of a TEM in our local hospital (the best available in NZ at the time) to study the electron diffraction dot patterns of fibrils from 5 to 15 nm diameter, and decided that the fibrils were built of cylindrically-wrapped graphitic sheets. This is basically the structure accepted for carbon nanotubes today. This was presented to an American carbon conference in the US in 1979, and shortly after, samples of our electrode tips were sent to five leading university laboratories around the world whose researchers had expressed Figure 3 (left): The side view of the arc of our continuous reactor, treating a carbon fabric that moves past the arc (see arrow). The arc is struck between a negative carbon electrode and the fabric, across a gap of around 10 mm.




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interest, including two in Japan. We had no idea of the practical possible uses and it was merely a curiosity for us. We did not publish the structural work in a journal, and even the conference did not have a permanent record of the full paper, as the paper was added as a loose page just before the conference. Even though it had been sent to the conference organizer in plenty of time for inclusion, somehow the (snail) mail was lost, and had to be sent again. We moved our research away from this area of arcs and carbon materials for almost 20 years until a worker (John Foulkes) in the nanotube field from Cambridge, UK, emailed a query about a structural analysis promised in our 1978 paper. We sent him a copy of our 1979 presentation, and he replied immediately, adamant that we had discovered the essential structure of carbon nanotubes 13 years before the Japanese worker Iijima. John was insistent that we publish something to correct the public record. We decided that the best move would be to contact the journal Carbon, in which our earlier work was published. The editor at the time was in fact the person who organized the 1979 conference, and he still had a copy of the original full presentation in his files! He encouraged us to publish it in Carbon (1999, 20 years after presentation) as an historical item, along with a thoughtful editorial describing our work and some even earlier work with some simpler observations. This led to the journal Nature commenting on the discovery in their decade review (1991–2001) of carbon nanotubes since Ijima’s paper, in an insert titled ‘Who saw the first nanotube?’ Their lead writer Philip Ball wrote,“The contrast (of reception of our work) with the excited reception of Iijima’s paper is remarkable, and illustrates how new discoveries rely on the prevailing research climate. In an age before nanotechnology and the fullerine-induced interest in carbon chemistry, there seemed little reason to regard the fibres as anything more than a smaller version of familiar micrometre-scale carbon fibres.”

Commercial process

ask-a-scientist

That could have been the end of our story, but an encounter with one of the group who found the buckyball (Robert Curl, who was visiting Canterbury University) led to a discussion about the high cost of



nanotubes and the need for a cheaper production method for nanotubes. We set about devising an economic process to deposit carbon nanotubes. We knew as chemical engineers that a continuously fed arc process would be much cheaper than the batch arc process used in all other labs, with much lower labour costs. It took us some years to achieve success where we could feed a flexible carbon fabric from a roll, through the arc for reliable deposition of nanotubes and out again onto another roll; a continuous, cheap process. (Figure 3 - an image of arc on substrate). This required finding all the important experimental variables. As is typical of such investigations, before we found all of them, the results were always rather random – sometimes we had nanotubes, sometimes we did not. After realizing which were important, we could control them and reliably find nanotubes. To keep the cost down, we did not want to have to seal out the atmosphere with expensive vessels, and so it needed to be done at atmospheric pressure. This was achieved through the valiant efforts of a list of research students, both local and international. The process now has international patents pending and the product is being groomed for various applications – including electrodes in batteries and other energy related devices. It may be of interest that our discovery story is being permanently displayed as a local science exhibit in the science centre ‘Science Alive’ in Christchurch. As part of this exhibit, they display the original reactor where the first samples were made in 1977–79. For further information contact: john.abrahamson@canterbury.ac.nz

References Abrahamson, J. (1974) Graphite sublimation temperatures, carbon arcs and crystallite erosion. Carbon, v12, 111-41. Abrahamson J., Wiles P.G., & Rhoades, B.L. (1999) Structure of carbon fibres found on carbon arc anodes. Carbon, v37, no11, 1873-4. (Republication of a paper presented to a 1979 Carbon conference in the US, because of historical significance). Ball, P. (2001) Roll up for the revolution. News Feature, Nature, v414, 142-144. Especially see the box insert “Who saw the first nanotube?” Iijima, S. (1991) Helical microtubules of graphitic carbon. Nature, v.354, 56-58. Thrower, P. (1999) Novel carbon materials – What if? Editorial in Carbon, v.37, 1677-1678. Wiles, P.G., & Abrahamson, J. (1978) Carbon fibre layers on arc electrodes – their properties and cool-down behaviour. Carbon, v16, 341-49.

ask-a-scientist createdbyDr.JohnCampbell I have been reading about the amazing discovery of a 5000 year-old-man, the `ice mummy’. He was dated by carbon-14 dating. What is this and how does it work? Edward Winter, Heaton Normal Intermediate School. Scientist Tom Higham, a radiochemist then with the Radiocarbon Dating Laboratory at Waikato University, responded: The `Iceman’ was discovered in 1991, preserved in ice in the alpine region between Austria and Italy. To find out when the Iceman died, radiocarbon dating was applied. This is a scientific dating method which is used in over 120 laboratories around the world. A living organism is constantly incorporating carbon into its body through food uptake, which builds bones, skin and hair. A small part of the carbon we consume is called `radioactive’ carbon or simply radiocarbon. Radioactive means that it has an unstable atomic structure. This means that after a certain period of time, carbon-14 decays or disappears. As long as a living

organism is taking up carbon, it is keeping the carbon-14 in its body at a constant level, but when death occurs, the carbon-14 begins to disappear and is not replaced. In the 1950s, scientists discovered that carbon-14 disappears at a known rate. They found that every 5568 years, half the carbon-14 left in the remains of an organism has gone (the radiocarbon `half-life’), so by measuring the carbon-14 remaining, they were able to calculate independent ages for carbon samples from archaeological sites. We can date carbon samples from today, back to about 60 000 years ago using this method. Tiny fragments of the Iceman’s bone, skin and grass from his boots have been dated in two radiocarbon laboratories, in Oxford and Zurich. (A piece of grass or skin about the size of one grain of rice is needed for a date). The dates placed the age of the Iceman between 3400-3100 B.C., or about 5500 years ago, the oldest example of a well-preserved human body ever found. For further information: questions@ask-a-scientist.net


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It is probably fair to say that today’s society runs on hydrocarbon fossil fuels. Not only are they used as fuels, many derivatives are indispensable as plastics, etc. The total combustion of hydrocarbons leads ultimately to water and carbon dioxide, in itself a major contributor to the greenhouse effect. However, incomplete combustion leads to carbon monoxide, which is toxic, and a variety of other unpleasant compounds, as Douglas Russell, Professor of Physical Chemistry, University of Auckland explains: The thermal decomposition of hydrocarbons in the absence of oxygen (pyrolysis) leads exclusively to large complex molecules. Hydrogen is lost from the system and carbon starts to bind to itself, resulting in increasingly large ensembles of fused planar carbon rings instead of chains, known as Polycyclic Aromatic Hydrocarbons or PAHs. (Refer Figure 1). PAHs are also extremely hazardous, being linked with cancer and mutations. Untuned motor vehicles emit a lot of soot and smoke (soot is essentially large clusters of PAHs), which have been related to an increasing trend in lung cancers and other diseases amongst urban populations.

Figure 1: Benzene forms from a variety of small hydrocarbons in combustion and pyrolysis; as the reactions go on, benzenes fuse to form PAHs, then eventually planes of carbon in the form of soot and graphite. Under special conditions, PAHs may form ball-like fullerenes or cylindrical nanotubes. As PAHs grow in size, the relative amount of hydrogen decreases; under some conditions, ensembles 60 carbons in size may lose all hydrogen and the carbon skeleton shifts from planar carbon rings to the spheres known as fullerenes – these too are shown in Figure 1.

Bucky balls C60 was the first fullerene discovered, formally named Buckminsterfullerene after its similarity to the geodesic dome of Richard Buckminster Fuller, but colloquially known as a bucky ball after its resemblance to a soccer ball. Next in size is C70, more like a rugby ball. With increasing size, the fullerenes become more axially stretched and eventually resemble graphite sheets wrapped into long tubes and capped at both ends with half a bucky ball; these are known as carbon nanotubes. Even more unusual structures can form: fullerenes can be trapped inside larger fullerenes, forming ‘carbon onions;’ nanotubes may be trapped inside larger nanotubes forming multiwall carbon nanotubes; several fullerenes may be trapped inside a nanotube forming a ‘carbon peapod.’

carbon

making carbon footballs from scratch This family of compounds possesses a number of unique properties that make them extremely useful. Their remarkable shapes have led to a great deal of research in the pharmaceutical industry1. C60 readily occupies the active site in the HIV protease enzyme (for example, see Sijbesma et al., 1993) blocking its action and therefore inhibiting the disease. They have also been looked at regarding their use as a rigid molecular scaffold for the attachment of other chemical groups to be used as drugs; in some instances, these groups have been designed to leave the bucky ball slowly, which has potential in designing slow-release medication. Their high surface area to volume ratio has also seen them as candidates for storing hydrogen in fuel cell applications (Ni, 2006). Also of interest are the electronic and magnetic properties of the fullerenes and nanotubes. They readily give up electrons, especially when exposed to light, and so are currently the focus of a great deal of research into new, efficient solar-cell based electronics. Fullerenes encapsulating small metals (termed endohedral fullerenes) have been discovered to be high temperature superconductors; if one is in turn encapsulated inside a nanotube (a very simple carbon peapod) and moved to either end of the nanotube, this may potentially correspond to the 1’s and 0’s utilized by computers in an approach to molecular memory storage (Kwon et al., 1999). Out of the vast array of potential applications and experiments currently being studied worldwide, some seem to belong to the realm of science fiction. Recently, it was discovered that two or three long nanotubes may wind around each other, forming a nanorope; long nanotubes have also been tied together, fittingly known as nanoknots. This suggests ideas of nanoscale machines. This too, unbelievably, is underway; in 2005, a group at Rice University successfully made a molecular based chassis with fullerene wheels that rolled over a gold surface when heated to 200°C (Shirai et al., 2005).

How are bucky balls formed? Hydrocarbon pyrolysis is often used for the synthetic preparation of fullerenes. The hydrocarbon starting material is cheap, and conditions can be altered to gain some control over the size of the fullerenes or nanotubes; however, this still only yields about 20% (by mass/vol.) fullerenes, and is therefore not ideal for large-scale production. Determining how fullerenes form (still a hotly-debated issue) is of obvious importance here; if we know how they form, we know what conditions we need to change to optimize their production. Furthermore, to know how fullerenes form we need to know how PAHs form; this will lead to improved incineration techniques, better air quality, and therefore lower incidences of lung cancers and respiratory diseases. Unfortunately, high temperature reactions are very chaotic; many different pathways are available, and a wide range of products form (all of which can undergo further reaction), making it exceptionally difficult to identify the most important steps. One of the more widely accepted routes, however, is based on observation that acetylene (the most stable hydrocarbon) 1

http://www.rsc.org/chemistryworld/Issues/2005/December/nano.asp




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accumulates in most pyrolysis systems; this is the hydrogen abstraction - acetylene addition (HACA) mechanism. To illustrate how the HACA mechanism works we will use ethene, C2H4, as an example. The important initial reactions are: C2H4  C2H3 + H (1) (Initiation - slow) C2H4 + H  C2H3 + H2 (2) (Fast) C2H3  C2H2 + H (3) (Fast)

The first step (the initiation step) requires a lot of energy, and is consequently very slow; but as H atoms are extremely reactive, (2) (which also gives vinyl, C2H3, radicals) is very rapid. The small concentration of H atoms produced in (1) is quickly consumed by (2); however, C2H3 is unstable, and quickly gives acetylene, C2H2, the PAH building block, and replenishes the H atom concentration at the same time. The result is a very fast radical chain reaction; the small pool of H radicals produced slowly in step (1) are rapidly used in step (2) and continually replenished in step (3). C2H3 is also very reactive, so as well as decomposing to C2H2 it can readily add to the accumulating C2H2 to give C4H5, (4). Just like C2H3, C4H5 can readily decompose to a stable molecule via (5) to give C4H4, or add to another acetylene to give C6H7 and then benzene via (6); stable molecules e.g. C2H4 and C4H4 can also have H abstracted from them to generate new radicals as in steps (2) and (7): C2H3 + C2H2  C4H5 C4H5  C4H4 + H C4H5 + C2H2  C6H7 C4H4 + H  C4H3 + H2

older work looking at C2HCl3 using models similar to that discussed in the previous section did use estimated C-Cl bond strengths in C2Cl3 lower than C-H bond strengths in C2H3, as expected, and found the C2H3-type model worked (Taylor et al., 1994). However, newer research measuring these bond strengths show the estimates were not low enough, and more recent measurements of the rate at which C2Cl3 dissociates suggests that it does not last long enough to react appreciably to form larger molecules, instead decomposing to the stable C2Cl2 (Bryukov et al., 2003). This is where our work comes in.

Figure 2: Acetylene may undergo addition to itself; the higher the energy of this process, the less likely it is to occur. Chlorinated acetylenes readily undergo this sort of reaction, as shown at the right.

(4) (5) (6) (7) etc

Analogues of steps (4) and (6) show how we obtain PAH growth in these systems by successive acetylene additions to hydrocarbon radicals; step (5) acts to slow this process by removing radicals, but these can be regenerated in steps similar to (2) and (7). These hydrocarbon chains are expected to wrap themselves into rings forming PAHs, with benzene, C6H6, representing the first such ring and the nucleus from which PAHs grow, losing more H atoms as this happens. Just how this random process leads to only the most condensed fused ring systems instead of rings with side C2 groups, and particularly how these close to give fullerenes, is still actively debated.

Figure 3: With chlorine present on only certain carbon atoms different mechanisms forming the same type of product can be tested as each mechanism predicts different product isomers.

How adding chlorine affects the system – novel molecule-molecule reactions.



The growth of similar molecules from chlorinated precursors is also very important given the toxicity of pyrolytic products in the incineration of wastes like dichloromethane and trichloroethylene, but has received much less attention. The products are similar to those seen in Figure 1, and traditionally the mechanisms postulated are similar to those discussed in the previous section. However, in reactions (1), (3), and (5), a Cl atom is preferentially lost where possible, as C-Cl bonds are much weaker than C-H bonds, and in reaction (2) a Cl atom removes H to form HCl, which is much more stable than either H2 or Cl2. This has appeared to work well, so little detailed work has gone into these processes. Closer examination, however, reveals some problems with this view. Of particular importance are bond strengths:

Figure 4: 5-membered ring migration in acenaphthylene leads to itself, so no reaction is observable; with partial chlorination, new isomers form and the ring migration reaction can be observed experimentally. In the absence of the radical reactions (1) to (7), we have direct molecule-molecule reactions. The energy of the initial step of these reactions may be calculated (see below); the energies are shown in Figure 2 for 2C2H2, 2C2HCl, and 2C2Cl2 from our most accurate calculations.


Using chlorine to ‘label’ carbon atoms 1. How to grow rings Chlorinated hydrocarbons may also provide insights into how increasingly large molecules arrange themselves into the PAH and fullerene-like structures that are observed. In particular, with mixed carbon/hydrogen/ chlorine systems, a Cl atom attached to a carbon may ‘label’ that carbon, distinguishing it from carbons with hydrogen attached. An example of carbon labeling involves the elucidation of a possible mechanism of formation of hexachloronaphthalene. Naphthalene has two fused benzene rings with eight hydrogens attached; there are ten different ways (isomers) of replacing 6 hydrogens with chlorines, but they do not all form in equal abundances during experiments. The mechanism of formation dictates the yields of each, and these yields may be varied by adding different chlorobenzenes and chloroacetylenes to the reaction; this shows that larger structures form from benzene, a basic assumption of the HACA pathway. Figure 3 shows one example of a chlorobenzene (1,2,3-trichlorobenzene) and chloroacetylene (dichloroacetylene) pair. The first mechanism shows a traditional HACA sequence leading to chlorinated naphthalene through the easiest possible route; however, the naphthalene predicted is not observed as a major product. The second mechanism examines an entirely different route: it adds a C4 species (rapidly formed by the molecule-molecule routes discussed in the previous section) that ‘coils’ itself on to the benzene radical. The expected product through this pathway is observed; further, varying the trichlorobenzene isomer added leads to isomers as predicted with the non-traditional C4 mechanism. Without chlorine labeling of carbon the products in both reactions are identical, and much less direct and definitive methods to identify the mechanism of formation are needed.

2. How to move rings An important feature of fullerene formation is the introduction of curvature, since precursor compounds like benzene and naphthalene are flat. The necessary curvature arises when 5-membered rings are introduced. For fullerenes, this alone is not enough; there must be twelve 5-membered rings at precise positions. This is one barrier in producing large quantities of fullerenes instead of toxic by-products: only a small number of 60-carbon sized clusters will have rings in exactly the right sites for cage closure. At high temperatures, 5-membered rings can move themselves around a PAH; if low enough in energy this process may be fast enough to place rings in the right place to lead to fullerenes. We have calculated these energies for a few larger PAHs, with and without chlorine, and found that chlorine lowers the energy needed for these rearrangements; this agrees well with experimental evidence that shows chlorine helps increase the yields of fullerenes formed (Alexakis et al., 1997). Experimental evidence to support theory is of course essential. The smallest system which can undergo these ring shifts are the acenaphthylenes (see Figure 4). Just

as in naphthalene, several distinct isomers are possible when partially chlorinated. The 5-membered ring migration for acenaphthylene, shown in Figure 4, leads to acenaphthylene again, and therefore no observable change. Heptachloroacenaphthylene undergoes a similar reaction more readily but produces a new isomer, also shown in Figure 4. As with naphthalene a particular choice of starting material leads to unique isomer yields. The higher the temperature employed structures with only a few chlorines present retain these particular yields; however, we obtain the same spread of heptachloroacenaphthylene isomers regardless of the starting materials. This suggests that, with more chlorine present, isomers of acenaphthylene and larger PAHs are selectively formed but are able to then convert to the more stable isomer producing an equilibrium profile of isomer regardless of the initial conditions.

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In the absence of chlorine, the energy barrier to reaction is very high, implying that reaction is unlikely to occur. For C2HCl and C2Cl2, however, the barrier is considerably lower, and as the concentrations of important radicals are lower too, molecular reactions may dominate. Furthermore, larger molecules with an acetylene-like group can undergo this kind of reaction and may explain additions at any stage of the reaction where the corresponding radical decomposes too quickly to react.

How we carry out our studies We have used a variety of experimental and theoretical techniques in our studies. In our pyrolytic technique of Infrared Laser Powered Homogeneous Pyrolysis (IR LPHP), a small Pyrex cell filled with reagents and a photosensitizer, SF6, is exposed to IR CO2 laser radiation; SF6 absorbs the radiation and converts it to heat. Reaction products are monitored by IR spectroscopy, which identifies molecules on the basis of their unique vibrations. For greater sensitivity, samples of the vapour (withdrawn using a syringe) or solid product are analyzed via GC-MS coupling gas chromatographic separation with highly sensitive mass spectrometric detectors (Russell 1990 and 2008). Experimentally determined reaction pathways are backed up by solving quantum theory’s equivalent of the conservation of energy, the Schrödinger equation, with commercially available software for representing molecular structures along hypothesized reaction pathways. The lowest energy path is the most likely candidate for describing the reaction mechanism.

Conclusions Careful analysis of partially chlorinated PAHs produced in combustion systems may provide insights into mitigating toxic pollutants produced during waste incineration and controlled formation of fullerenes. Chlorine may help label where carbon atoms come from in growing structures, and may even enable low energy routes not present in non-chlorinated systems leading to higher yields of larger structures suited for fullerene and nanotubes formation. For further information contact: d.russell@auckland.ac.nz

References Alexakis, T., Tsantrizos, P.G., Tsantrizos, Y.S., &Meunier, J.-L. (1997). Synthesis of fullerenes via the thermal plasma dissociation of hydrocarbons. Appl. Phys. Lett., 70, 2102-2104. Bryukov, M.G., Kostina, S.A., & Knyazev, V.D. (2003). Kinetics of the Unimolecular Decomposition of the C2Cl3 Radical. J. Phys. Chem.,A 107, 6574-6579. Kwon, Y.-K., Tomanek, D., & Iijima, S. (1999).“Bucky Shuttle” Memory Device: Synthetic Approach and Molecular Dynamics Simulations. Phys. Rev. Lett., 82, 1470-1473. Ni, M. (2006). An overview of Hydrogen Storage Technologies. Energy Exploration & Exploitation, 24, 197-209. Russell, D.K. (1990). Infrared Laser Powered Homogeneous Pyrolysis. Chemical Society Reviews, 19, 407-437; (2008): Reaction Mechanisms in the Gas Phase Studied by Laser Pyrolysis, in Lasers in Chemistry, ed. M. Lackner, Wiley-VCH, Weinheim, 839-860. Shirai, Y., Osgood, A.J., Zhao, Y., Kelly, K.F., & Tour, J.M. (2005). Directional Control in Thermally Driven Single-Molecule Nanocars. Nano Lett., 5, 2330-2334. Sijbesma, R., Srdanov, G., Wudl, F., Castoro, J.A., Wilkins, C., Friedman, S.H., DeCamp, D.L., & Kenyon, G.L. (1993): Synthesis of a Fullerene Derivative for the Inhibition of HIV Enzymes. J. Am. Chem. Soc., 115, 6510-6512. Taylor, P.H., Tirey, D.A., Rubey, W.A., & Dellinger, B. (1994). Detailed modeling of the Pyrolysis of Trichloroethene: Formation of Chlorinated Aromatic Species. Combust. Sci. and Technol., 101, 75-102.




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sustainable steel construction and embodied CO2 assessment Have you ever considered the impact of building construction on carbon dioxide emissions? Clark Hyland, Manager, Steel Construction New Zealand Inc, explains why steel building construction is more sustainable and has a lower carbon footprint. Why is sustainable construction important? As well as being economically important, construction is important socially. In Britain, construction output makes up 8% of GDP and people spend 90% of their lives in buildings, and these figures are probably similar for New Zealand. Obviously, the quality of our lives is therefore strongly influenced by the quality of the built environment. This in turn makes an impact on resource depletion, not to mention construction and demolition waste. And two other British statistics are quite telling: 10% of all the UK’s energy is expended on the production of construction materials; while 50% is expended in the operational use of buildings. (Sansom et al., 2008). Increasingly in New Zealand, clients who commission construction projects are looking for suppliers of building components to provide evidence of sustainable practice. Responsible sourcing requires that ISO 14001 environmental management systems be in place, not only to facilitate the traceability of product origins, but also what should be done with building products at their end of life, otherwise known as end of life stewardship. If steelwork is marked in such a way that its mechanical properties can be reliably identified upon demolition of a structure, then the most effective reuse of steel products can be made. Such a marking protocol is currently being introduced into the New Zealand Steel Structures Standard NZ3404. The methods for the quantitative measurement of sustainability in construction are still in their infancy around the world. Yet single-issue criteria such as embodied CO2 emissions have the potential to dominate thinking and hinder development of a robust life cycle assessment (LCA) methodologies that effectively take into account all environmental impacts. Methodologies are needed that can be applied to all construction materials in a consistent and fair manner, and therefore encourage better environmental outcomes from all forms of construction.

Sustainability credentials of steel buildings The Earth is an iron planet, iron being by far the most common chemical element in its makeup. Our planet is endowed with an estimated, recoverable (using current technology) global reserve of 800 billion tonnes of iron ore. In addition, the UK alone has 100 million tonnes of constructed steel stored, as it were, in the country’s infrastructure. Steel is a useful building material because the strengthto-weight ratio of structural steel enables us to build large (relatively light) structures with smaller foundations

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such that structural efficiency equates with resource efficiency. Steel is a low waste product and is 100% recyclable (many times over) without loss of its mechanical properties. Also, more than 90% of the by-products of iron and steel production are recycled. And all of the 1– 4% ‘steel wastage’ that occurs in manufacture is recycled. Globally, more than 400,000 kilotonnes of steel are recycled annually. It is one of the few structural building materials that can be truly recycled. It is important to note that concrete cannot be recycled back into concrete; it can only be down-cycled i.e. crushed for use as hardcore roading material or general construction fill. The reuse of steel takes place at two levels: the product can be shot-blasted and re-fabricated after demolition of a building structure. It is also possible, with sufficient foresight, for buildings to be dismantled and re-erected elsewhere. For example, the aquatic centre for the Sydney Olympics has been dismantled and re-erected as a rugby league stadium in Wollongong. Architects and structural engineers are becoming increasingly innovative, creating buildings that feature a range of sustainability advantages to be obtained in structural steel. In the 60-year life of an office building, the typical ratio of embodied energy, put in during production and construction of the building components, compared to that of the building’s operational energy, is 1:8 (Eton, Amato, 1998). It therefore makes sense to concentrate on reducing the 8 rather than the 1. However, there is also significant interest in reducing embodied energy impacts. The biggest potential for minimising the embodied CO2 emissions footprint of a construction project rests with the designer’s ability to configure the building in such a way that the structure’s weight is minimised and the level of end of life reuse and recycling of the construction products used is maximised.

Dual life cycle assessment method A dual life cycle assessment model has been proposed to assess the CO2 emissions of buildings (see Figure 1) (Hyland & Xiao, 2008). This follows an ISO 14040 approach with identification of appropriate system boundaries, inputs and outputs relevant to the dual steel making processes that steel products move through during initial production and recycling. Steel construction products are considered at a global level, as steel products are both produced locally and imported into New Zealand from a variety of sources. At the end of each product life cycle, the recovered steel is reused or recycled locally, or it is exported as scrap. The dual life cycle model considers two life cycles of the construction materials specified in a project that is effectively rebuilt after demolition incorporating the resulting reusable, recyclable and new materials required. This is an important analytical approach for highly


Case study: comparing three equivalent tenstorey buildings

Figure 1: ISO 4140 Steel Life Cycle Assessment System. recycled materials such as steel. The greatest reductions of CO2 emissions are achieved by minimising the end of life loss of steel products and maximising their reuse or recycling. All steel-making requires a certain amount of iron which must initially be produced by the primary or integrated (INT) iron and steel making process. This involves the mining of iron ore, iron making and then conversion of the iron into steel. Recovered scrap steel can be recycled directly through the secondary steel making process of an Electric Arc Furnace (EAF) process which requires a reduced input quantity of iron. Scrap steel is also needed as part of the primary integrated steel making process. The EAF process has a significantly lower carbon footprint than the integrated process so it is desirable to maximise the recovery of scrap steel available for secondary steel making. If steel products at the end of life of a building are unavailable for recycling in the integrated or EAF steel making processes, then replacement steel must be made by the more carbon emissions intensive integrated iron and steel making process. It is generally acknowledged that the making of iron and steel is responsible for between 3–4% of manmade greenhouse gas emissions. In the two processes, integrated iron and steel production amounts to 60% of the global output, and 40% is produced by the Electric Arc Furnace (EAF) method. The latter uses 90% steel scrap, whereas the integrated method uses 15–20% steel scrap. Total world production stands at 1,300,000 kt, of which EAF-made steel accounts for less than 500,000 kt. The current available pool of scrap steel globally is estimated to be sufficient for the production of only 45% to 55% of the steel products required. Steel scrap is a sought after internationally-traded commodity with strong commercial forces driving its recovery for EAF steel making. Even so, large volumes of new iron and steel production via the integrated process are necessary to meet consumer demand. Both the EAF and integrated production processes are therefore essential as part of the steel product life cycle system. The specification of recycled steel input percentages to building projects to avoid the integrated process route

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does not address the need to minimise the CO2 emissions of steel making. However, it is recommended that the supplier be asked to show evidence of achievement of emissions’ limitations and reductions. For example, New Zealand Steel advises that it met its voluntarily agreed emissions’ reductions’ targets, which the New Zealand government set in the mid 1990s, by the year 2000.

The embodied fossil fuel derived carbon footprint of three equivalent New Zealand ten-storey buildings has been assessed (Hyland, Xiao, 2008). The buildings have the same architectural envelope with 9900m² gross floor area and are based on those designed for New Zealand loading conditions. The combined superstructure and the foundation embodied CO2 emissions of each option were assessed using the dual life cycle method and are plotted based on Australian LCI data (Strezov, Herbertson, 2006) and New Zealand concrete LCI Data (Alcorn, 2003) in CO2 Emissions Plots in Figure 2. The Australian data is relevant as Australian sourced steel sections are used by local steel fabricators to make up around 60% of the structural steelwork used in New Zealand buildings. Using Auckland reinforced concrete recovery rates on demolition, it was found that the all-steel option (EBFSGF), incorporating eccentrically braced frames and composite cold-formed metal-deck slab with steel beams and columns, had the smallest footprint at 1356 tCO2 or 0.137 tCO2/m2. The foundation component was 138 tCO2 or 10% of this total. The hybrid steel/concrete option (SWSGF), incorporating reinforced concrete shear walls and composite coldformed metal-deck slab with steel beams and columns, had emissions of 1579 tCO2 or 0.159 tCO2/m2. The increased foundation size made up a large amount of the difference between this and the all-steel option (EBFSGF), being 231 tCO2 or 15% of this total. The all-concrete option (SWCGF), utilising reinforced concrete shear walls and timber in-filled, hollow-core slab on pre-cast concrete beams and reinforced concrete columns, had a carbon emissions footprint at 1513 tCO2 or 0.153 tCO2/m2. The foundation cost was similar to that of the hybrid steel/concrete option (SWSGF) being 246 tCO2 or 16% of this total. Both options reflected the need for significant foundation works to support the concrete shear wall elevator cores.

Figure 2: CO2 Emissions Plots using Australian Steel and New Zealand Concrete LCI Data.

Conclusion The assessment of the embodied CO2 emissions of building products needs to be done in the context of the assessment of the structural building system within which they will be incorporated. In summary full steel

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construction options incorporating cold-formed metaldeck slabs for multi-storey buildings offer CO2 footprint advantages over hybrid steel/concrete and full-concrete options, particularly when foundation CO2 footprint emissions are included. While steel itself has a higher carbon footprint per tonne than a tonne of reinforced concrete, it allows a lower carbon footprint to be generated per square metre of building construction. This is consistent with its higher strength to weight ratio compared to that of concrete. The best improvement in environmental impacts related to construction is expected to come from the development and application of robust life cycle assessment methods that can be applied consistently to all construction materials on a project by project basis. A life cycle assessment methodology needs to account for

reuse, recycling and down-cycling of each material. The dual cycle method incorporates these factors. The ability to easily reuse and recycle steel is its most enduring environmental attribute, and one that other construction materials have difficulty competing with. For further information contact: clark.hyland@scnz.org

References Alcorn, A. (March 2003). Embodied Energy and CO2 Coefficients for NZ Building Materials. Victoria University of Wellington. Eaton, K.J., & Amato, A. (1998). A Comparative Environmental Life Cycle Assessment of Modern Office Buildings. Steel Construction Institute, Ascot. Hyland, C.W.K., & Xiao, H. (April 2008). Comparative CO2 Emissions Assessment of New Zealand Multi-Storey Structures, SCNZ–15. Steel Construction New Zealand Inc., Manukau. Sansom, M., Hyland, C.W.K., & Kane, R.J. (2008). Proceedings of the Sustainable Steel Construction Seminars April 2008. Steel Advisor, Steel Construction New Zealand Inc., Manukau. Strezov, L., & Herbertson, J. (April 2006). A Life Cycle Perspective on Steel Building Materials. Australian Steel Institute, Sydney.

preventing sudden death in the young University of Auckland researchers have established a new way to identify gene mutations, which will directly lead to improved diagnosis of those at risk of sudden cardiac death. Currently available genetic screening tests for long QT syndrome (LQTS) miss about a third of cases. Researchers at the University of Auckland’s Faculty of Medical and Health Sciences have recently made an important discovery which will significantly increase the diagnostic hit rate. Genetic diagnoses are important in LQTS because they identify the type of LQTS which guides treatment, and because they permit accurate family screening and genetic counselling. Carey-Anne Eddy, the PhD researcher involved in the project, working with Associate Professor Andrew Shelling said, “Current molecular genetic screening programmes identify the genetic cause in only about 70% of cases. This new test offers a dramatically improved success.” Long QT syndrome is an inherited disorder occurring in about 1 in 2000 people in New Zealand, which causes recurrent collapse and sudden death. It is the leading cause of sudden unexpected death in young people. “The risk of sudden death from LQTS can be significantly reduced with the correct medication and clinical treatment,” says paediatric cardiologist Associate Professor Jon Skinner of Starship Children’s Hospital. “However, the type of genetic mutation and gene in which it occurs, directly influences the type of treatment to which each patient will best respond. Knowing the genetic cause of LQTS in a family also allows extended family members to be screened and offered the most suitable life-preserving treatment and, therefore, has extreme clinical value.”

As part of a significant research endeavour to prevent sudden cardiac death in young New Zealanders, funded by Cure Kids, the research study analysed the DNA of twenty-six patients with LQTS identified by the Cardiac Inherited Disease Group (www.cidg.org) who had tested negative for LQTS gene mutations. The investigation, using new technology, revealed three patients (11%), carried mutations responsible for LQTS which the conventional genetic tests could not detect. The current standard genetic screening tests (called polymerase chain reaction, followed by genomic sequencing) can detect small changes in a person’s DNA. However, it can miss big deletions or large rearrangements of DNA. For this reason, the researchers used a recently described genetic screening method which picks up large-scale gene changes, known as multiplex ligation-dependent probe amplification (MLPA). The study identified two large deletions and one large duplication in genes that encode potassium ion channels in the heart. With certain triggers, like exercise or emotional stress, these mutations may cause an otherwise structurally-normal heart to undergo rhythmic changes which may lead to fainting, epileptic-like seizures and even sudden death. The research represents one of the biggest advances in the field since the discovery of the first three long QT genes over ten years ago, and will change the routine testing of this important disease. It is published in the September issue of Heart Rhythm. For further information contact: a.shelling@auckland. ac.nz


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carbon in soils Soils store substantial amounts of carbon (C) in soil organic matter, and the amounts are an important component in the global C cycle as Graham Sparling and Louis Schipper, Department of Earth and Ocean Sciences, University of Waikato describe: Carbon in the Earth’s rocks, oceans, atmosphere and soil Carbon is the fourth most common element in the galaxy (by mass) but does not even rank in the twelve most abundant elements on Earth. By far the most abundant source of carbon on Earth is in the crust as inorganic rocks such as calcite and limestone in marine and sedimentary deposits. These rocks have taken many millions of years to form. Other major inorganic sources are in the oceans and atmosphere. Carbon is also a major and essential constituent of living creatures, and is present in organic forms, but the amount present as living plants and animals or as dead plants and animals (litter, organic matter and fossil fuel deposits) is small compared to that in rocks (Table 1). The organic forms of carbon in soil are often referred to collectively as soil organic matter, humus, or soil carbon. In fact soil organic matter is about 60% carbon, and comprises the largest terrestrial store for organic C, more than in living plants and animals. Table 1: Estimated major stores of carbon on the Earth Store Marine Sediments & Sedimentary Rocks Ocean Fossil Fuel Deposits Soil Organic Matter Atmosphere Terrestrial Plants

Amount in Billions of Metric Tonnes 66,000,000 to 100,000,000 38,000 to 40,000 4000 1500 to 1600 578 (as of 1700) to 766 (as of 1999) 540 to 610

Figure 1: The amount of nitrogen stored in soil is closely linked to the total carbon content. Organic matter has many other beneficial effects for soil, increasing the ‘exchange capacity’ of soils, which improves the ability of the soil to retain charged molecules such as calcium, magnesium, phosphates, sulphates and trace elements. Soil organic matter also forms both a habitat and food source for soil organisms and is the primary energy store for the soil detritus feeders.

Living organisms and the source of soil organic matter Carbon is an essential component of most molecules making up living cells, and responsible for their cell structure, biochemistry, metabolism and genetic code. Carbon enters the biosphere through the photosynthetic ability of plants and some micro-organisms using the energy from sunlight to take carbon dioxide (CO2) from air and water and make complex organic polymers and cellular components (Figure 2). In some very unusual environments such as parts of the sea floor or deep underground where light does not penetrate, conversion of carbon dioxide to bio-molecules is driven by the use of chemical energy.

Ref: The Encyclopedia of Earth. http://www.eoearth.org/article/Carbon_cycle

Benefits of soil organic matter The presence of organic matter C in soils alters the soil characteristics, usually in beneficial ways. Organic matter helps to bind the primary mineral particles, forming crumbs and aggregates. Aggregates help to reduce soil erosion and also give soil its crumbly texture. The crumbly texture makes it easier for plant roots to penetrate and for the soils to drain freely and still retain water. The presence of organic matter helps the soil to store plant nutrients. Among the most important of these nutrients is nitrogen (N) an essential macronutrient for plants and animals. Mineral rocks contain very little N. Most N in soils has been accumulated through biological processes such as N-fixation by legumes and their symbiotic bacteria, and by chemical inputs from fertilisers and nitrogen oxides in the atmosphere (from lightning forming nitrogen oxides). The ability of a soil to hold onto these sparse N sources is highly dependent on the amount of soil organic C (see Figure 1). When micro-organisms decompose soil organic matter this nitrogen becomes available to plants.

Figure 2: Average amounts of carbon in one hectare of terrestrial ecosystems and yearly inputs and losses of carbon. (Adapted from Janzen 2004). When plants or animals die, the carbon in their cells enters the soil and begins to decay, forming organic matter. The amount of ‘dead’ organic matter in soil is substantial: three to four times more than in the living terrestrial organisms, but this dead soil organic matter was initially all derived from the ‘fixation’ of atmospheric CO2 by photosynthetic organisms. The decay of this organic matter by soil organisms completes the carbon

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cycle converting the organic matter to carbon dioxide (Figure 2) and occasionally small amounts of methane. The living fraction of soil organic matter typically comprises 1–4% by weight of the soil organic C, and is concentrated in the upper layer of soil where the bulk of the organic matter accumulates. The living portion, the soil biomass, is a complex, numerous and very diverse community of bacteria, fungi, protozoa, nematodes and a huge range of microfauna. However, in terms of weight, bacteria and fungi are dominant and comprise about three quarters of the living mass.

Soil organic matter composition Soil organic matter is a complex mixture of compounds and differs in composition from soil to soil. As well as C, soil organic matter also contains large amounts of oxygen (O), hydrogen (H), nitrogen (N), smaller amounts of sulphur (S) and phosphorus (P) and a range of trace elements. Derived initially from the decomposing remains of plants, animals and soil microbes, the composition of soil organic matter is not static but is constantly undergoing continuing decay and transformation. It is organic matter that gives topsoil and composts their dark colour. Various means to characterize soil organic matter have been used over the centuries. Most organic matter is formed of complex aromatic (ring structured) and aliphatic (long chains) of condensed polymers of high molecular weight that are not easily identified. There is no single structure to soil organic matter because it is derived from a wide range of complex biological compounds, and the organic matter has often been reprocessed many times by soil organisms. Traditional classifications of organic matter relied on chemical or physical fractionation, for example, soil organic matter has often been separated into fulvic acid, humic acid and humin fractions, depending on its solubility in water, alkali or acid (Table 2). Carbon in the form of charcoal is found in many soils, and is more abundant where there has been regular burning of plant material. Table 2: Classification of soil organic matter fractions based on their solubility in alkaline and acid extractants Group of substance Water Fulvic acid Humic acid Humin

Soluble Sparingly Insoluble

Solubility in: Alkali

Acid

Soluble Soluble Insoluble

Soluble Insoluble Insoluble

Adapted from Vaughan and Ord 1985.

Because strong acids or alkali may modify the organic matter extracted from soil, it is questionable how useful such chemical extracts are, and the extracted fractions still have a very heterogeneous composition. More modern approaches use less drastic methods such as physical separation into ‘light’ and ‘heavy’ fractions (using floatation in a high density liquid).

The less decomposed material (such as relatively fresh shoot and root material) is generally ‘light’ and floats, whereas older, more highly degraded material is comparatively ‘heavy’ often being bound to clay particles. Modern analytical methods using spectrographs and pyrolosis − mass spectrography has revealed a huge range of compounds in addition to the long-chain plant polymers of lignin and cellulose origin. Additional compounds include lipids (fats and waxes), those containing nitrogen (amines and amides) and complexes of these constituents. To further complicate the identity of soil organic C, most organic matter in soil is intimately mixed with the soil mineral components, particularly clays, iron oxides and aluminum oxides and hydroxides. These form ‘organomineral complexes’ which modify both behavior of the clay and also the organic matter.

Amounts of organic matter in soils Soils typically contain around 1–10% organic matter C; New Zealand soils tend to be high in organic C compared to those in Australia and other arid countries. For New Zealand this translates to about 150 tonnes of organic C in the top metre of a hectare of soil. This is a result of high inputs of C from the previous forest vegetation, and the high productivity of our pastures, coupled with a temperate climate and some volcanic ash soils that are particularly good at stabilizing soil organic matter and preventing losses. The amount of organic matter in soil depends not only on the properties of the soil but also on the type of vegetation at the site (Table 3). In New Zealand, total C is usually accepted as a good measure of organic matter C, and hence total organic matter. This is because most NZ soils contain negligible amounts of carbonate, which would otherwise add to the total C content. Total C is usually measured in the laboratory by dry combustion or acid oxidation. If required, a factor of 1.7 is usually used to provide an estimate of percentage of soil organic matter (% total C × 1.7 = % soil organic matter).

Cycling of soil organic matter Most C in soil organic matter has taken many decades to accumulate. However, it does not continue to accumulate forever. Whether there are ongoing losses or gains depends on the balance between the inputs of fresh organic material to soil and losses through decomposition back to CO2 or losses through topsoil erosion. Long-term field trials (160 years!) from Rothamsted in England have shown that with regular inputs of organic matter the amount in soil slowly accumulates over many decades or even hundreds of years until an equilibrium is reached (Figure 3). It seems soils have the capacity to store only a defined amount of organic matter. Why does organic matter take so long to accumulate? When plant residues are added to soil, they start to decompose and after a year only some 30% remains,

Table 3: Estimates of the amounts and concentrations of soil organic C under different land uses summed for the whole of New Zealand (as in 2000, 0–30cm depth), and average amounts per hectare Land use Area (Millions of hectares)

Soil C (Millions of tonnes) Mean and standard error

Soil C content

( Tonnes ha-1)

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Grazing land

14.0

1480±58

105.7

Natural shrub vegetation

2.7

244±18

90.4

Cropland

0.3

26±3

86.7

Exotic forest

1.3

77±23

59.2 Adapted from: Tate et al (2005)


processes (both wind and rain) can also relocate topsoil, sometimes many kilometres from its original site. Fire may be useful to clear cereal stubble, but also reduces organic matter returns to soil.

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with 15–20% remaining after two years, and perhaps 10–15% after three years. The actual amount at any one time is a combination of the nature of the added organic matter, how long it has been there, the soil moisture and temperature. For example grass clipping disappear very quickly whereas bits of wood can remain for many years.

Figure 4: Losses of soil carbon following the conversion of land to continuous market garden in Pukekohe. (Adapted from Haynes and Tregurtha (1999)) Figure 3: Organic matter changes at the Rothamsted long-term trials. The dashed line is from a soil used to grow cereal without manure or fertiliser inputs, whereas the solid line is the same soil that has had continuous inputs of organic matter since the 1850s. The dotted line with open circles had added manure until about 1870 when no further inputs were made and soil C then declined. (Adapted from Poulton (1995)) The amount of organic matter held by soils also depends on the type of soil. Finer textured clay soils usually have more organic matter than coarse textured sandy soils. In New Zealand, mineral soils derived from volcanic ash normally have the greatest amounts of organic matter (8– 15% C). The average age of organic matter in mineral soils in New Zealand is about forty to sixty years, but this is only the average, and the organic matter is made up of an old stable fraction that may be hundreds or even thousands of years old; a fraction is five to sixty years old, and the most recent organic matter which may only be one to five years old, or even only months or days (the labile fraction). Some of the older, persistent organic matter in New Zealand pasture soils originally accumulated while the soils were still under the original forest trees. While organic matter accumulates only slowly in soils, its rate of decline and loss can be rapid. Soils that are regularly cultivated and used for growing crops invariably have much lower soil organic matter contents than the equivalent soils under forest or pasture. Figure 4 shows the change in organic matter C in a Patumahoe clay soil near Pukekohe used for intensive vegetable growing. The soils had accumulated organic matter during a long period under forests. Once cleared and used for arable cropping, the losses of organic matter occurred. Losses were fastest during the first ten years of cultivation, and occur because the decomposition of existing soil organic matter is increased because of tillage and the disruption of soil aggregates, while returns of fresh plant organic material are less because much of the produce is removed from the sites at harvest. Most methods of cultivation and tillage increase the rate of decomposition and loss (decomposition to CO2 gas) of soil organic matter. Alternative approaches to cultivation and cropping that are less physically disruptive and retain crop residues including minimum tillage or zero tillage (such as direct drill) can help retain soil organic matter. Even where there is no cultivation, inputs of fresh organic matter to soil are much decreased by the bare ground between row crops or horticulture with little ground cover. Subsequent harvesting leaves the soil bare, and removes a large proportion of the crop off-site. Erosion

Peat soils are unusual in having as much as 40–60% total C; hugely more than mineral soils. The extra organic content is because organic matter decomposition is slowed by the acid, wet, anaerobic conditions, and the organic C can persist for thousands of years under natural conditions. These organic peat soils are found throughout New Zealand but the largest areas are found in the Waikato, parts of the Bay of Plenty, the West Coast and Southland. However, even though the organic matter has persisted for thousands of years as peat, it is susceptible to decomposition particularly when these soils are drained to allow agricultural production. Drainage allows oxygen to enter the soil profile which can accelerate decomposition by micro-organisms. It is not uncommon for the surface of deep peat soils to decline by 1–2cm in just one year depending on land management. Avoiding over-draining these soils by keeping the water-table close to the surface can reduce peat losses.

Conclusion Soils store substantial amounts of C in soil organic matter, and the amounts are an important component in the global C cycle. Soil carbon is critical to the maintenance of healthy soils, improving their structure, allowing infiltration of water and air, holding on nutrients important for plant growth and as food and habitat for a wide array of soil organisms. The forms of soil organic matter are complex and decompose at different rates, but are all originally derived from input from plants and animals. Land management practices can alter the amount of C held in soils, often soil C is lost more quickly than it is gained and so careful stewardship of our land is needed. For further information contact: schipper@waikato.ac.nz

Acknowledgements We thank Kevin Tate and Roger Parfitt for their comments. This work was funded by the University of Waikato and a FRST-subcontract from Landcare Research.

References Haynes, R. J., & Tregurtha, R. (1999). Effects of increasing periods under intensive arable vegetable production on biological, chemical and physical indices of soil quality. Biology and Fertility of Soils, 28, 259-266. Janzen, H. H. (2004). Carbon cycling in earth systems – a soil science perspective. Agriculture, ecosystems and environment, 104, 399-417. Poulton, P. R. (1995) The importance of long-term trials in understanding sustainable farming systems. The Rothamsted experience Australian journal of experimental agriculture, 35, 825-834. Tate, K. R., Wilde, R. H., Giltrap, D. J. , Baisden, W. T., Saggar, S., Trustrum, N. A., Scott, N. A., & Barton, J. P. (2005). Soil organic carbon stocks and flows in New Zealand: System development, measurement and modelling. Canadian Journal of Soil Science, 85, 481-489. Vaughan & Ord (1985). Soil organic matter – A perspective on its nature, extraction, turnover and role in soil fertility. In Soil Organic Matter and Biological Activity (D. Vaughan and R.E. Malcolm Editors) Developments in Plant and Soil Sciences Volume 16, pp1–35. Martinus Nijhoff/Dr W Junk Publishers, Dordrecht.

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measuring carbon stocks in our forests, shrublands and soils How do you measure carbon stocks in New Zealand’s forests, shrublands and soils? In this article, Ian Payton, Landcare Research, takes readers on a short walk through part of the climate change labyrinth. As a signatory to the United Nations Framework Convention on Climate Change (UNFCCC), New Zealand is required to report annually on greenhouse gas (carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulphur hexafluoride) emissions and removals.1 The Kyoto Protocol (a subsidiary agreement under the UNFCCC which New Zealand ratified in 2002 and which came into force in 2005) further commits New Zealand to reducing its greenhouse gas emissions to 1990 levels (refer Figure 1) during the first commitment period (CP1)2 or taking responsibility for any excess. In practical terms, taking responsibility means offsetting increased emissions by developing carbon sinks, or purchasing emission reduction units from parties to the Protocol that have exceeded their target. Development of carbon sinks during CP1 is limited to afforestation3 and reforestation4 that has occurred since 1990, balanced by any deforestation5 that has occurred over that period.

Over the last 10–15 years, researchers at Landcare Research and Forest Research (now Scion) have developed methodologies to enable the Ministry for the Environment to assess changes in carbon stocks in New Zealand’s indigenous forests, shrublands, planted forests, and soils. These build on existing methods and databases developed for other purposes. For indigenous forests and shrublands they are based on the National Vegetation Survey7 (NVS) permanent forest plot methodology, planted forests utilise the Permanent Sample Plot (PSP) methodology used by the forest industry, and soil carbon is assessed using methods developed for the National Soils Database. This article outlines how carbon stocks and carbon stock change is being assessed in each of these instances, to ensure New Zealand can meet the reporting requirements of the Kyoto Protocol. The GPG manual defines five terrestrial carbon pools, all of which need to be assessed. These are above-ground biomass, below-ground biomass (roots), dead wood (logs or fallen branches > 10cm in diameter), litter (dead leaves, twigs and branches up to 10cm in diameter), and soil organic matter. Above-ground biomass includes trees, shrubs, and herbaceous vegetation; although in forests the latter is often ignored as it forms only a minor part of the total carbon stock.

Measuring carbon stocks in indigenous forests and shrublands

Figure 1: New Zealand’s greenhouse gas emissions between 1990 and 2005. Carbon accounting and reporting procedures are determined by the Intergovernmental Panel on Climate Change (IPCC) and set out in their Good Practice Guidance (GPG) manual for Land Use, Land Use Change and Forestry (LULUCF).6 These allow countries to build on existing inventories, and aim to ensure that national inventories are comparable, complete, accurate, transparent, and consistent. In New Zealand the Ministry for the Environment is developing the Land Use and Carbon Analysis System (LUCAS) to quantify and report on changes to carbon stocks resulting from afforestation, reforestation and deforestation during CP1. The National Inventory report is available on the Ministry for the Environment’s website: http://www.mfe.govt.nz/publications/climate/ greenhouse-gas-inventory-overview-jul07/html 2 CP1 runs from 1 January 2008 to 31 December 2012. 3 Establishment of forest on land that has not been in forest for a long time. 4 Establishment of forest on land that was not forested on 31 December 1989. 5 Conversion of forested land to non-forested (e.g. agricultural) land 6 Available from the IPCC website: http://www.ipcc-nggip.iges.or.jp/public/gpglulucf/gpglulucf.html 1

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For indigenous forests and for shrublands, carbon stocks are estimated using a national network of permanent plots, located on an 8km2 grid covering the main islands of New Zealand and near-inshore islands such as Great Barrier Island and D’Urville Island (Figure 2). Permanent plots are preferred, although they require more effort (and therefore expense) to establish, because they factor out spatial variability that would otherwise mask the temporal changes being measured. The plot network was established over a 5-year period between 2002 and 2007, and is being remeasured between 2008 and 2012 (i.e. during CP1). Plots are located wherever an intercept on the 8km2 grid falls within an area mapped as indigenous forest or shrubland by the Land Cover Data Base version 1 (LCDB1)8, the most up-to-date land cover map of New Zealand at the time the plot network was being designed. A total of 1372 intercepts were identified and 1258 plots established. The remaining 114 points were either inaccessible (e.g. on bluffs), or on properties where the landowner refused access. Based on calculations from a pilot trial carried out in 1998, this intensity of plots is expected to provide a better than 95% probability that carbon stock estimates will be within 5% of the mean (± 10 tonnes/hectare) in indigenous forests, and 12% of the mean (± 2.6 t/ha) in shrublands.

NVS website address: http://nvs.landcareresearch.co.nz For more information go to: http://www.mfe.govt.nz/issues/land/land-cover-dbase/index.html

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Figure 3: Layout of 0.04-ha (20 Ă&#x2014; 20m) and 0.13-ha (20-m radius) plots used to assess carbon stocks in indigenous forests and shrublands.

Measuring carbon stocks in planted forests Figure 2: Permanent plot network for assessing carbon stocks in New Zealandâ&#x20AC;&#x2122;s indigenous forests and shrublands. Indigenous forest and shrubland plots are 0.04ha in area, with an extension to 0.13ha for large (> 60cm in diameter) trees (Figure 3). Height or length and diameter measurements are used to estimate the volume of trees (including tree ferns) and dead wood. This is converted to biomass using allometric equations and speciesspecific wood densities, and multiplied by 0.5 to produce a carbon estimate.9 Shrub biomass is estimated using height and width measurements to derive a volume, and off-site biomass harvests10 to relate volume to mass. Litter is estimated using quadrat harvests. Roots present more of a problem. Theyâ&#x20AC;&#x2122;re time-consuming (and therefore expensive) to harvest, and harvesting destroys the plot. The fallback position is to use existing studies that have measured above- and below-ground biomass to establish an above-: below-ground biomass ratio. That figure, while quite variable, averages out at around 25%. Once all the components have been summed, the final step in the process is to adjust the total carbon estimate for the slope of the plot. The plot-based estimates are combined to produce an average carbon value (tC/ha) for each vegetation type, which is multiplied by the area of that type to produce a national carbon stock estimate. Satellite imagery taken in 1990 (the baseline year for the Kyoto Protocol), 2008, and 2012 (i.e. the beginning and end of CP1) is being used to estimate area. The 1990 baseline map is expected to be completed in the first half of 2009, and satellite imagery has been obtained for the 2008 map. Carbon stock estimates from the initial measurement of the indigenous forest and shrubland plot network are currently being calculated. Based on earlier studies these are expected to average around 180 tC/ha for indigenous forests and 20 tC/ha for shrublands. Carbon stock change during CP1 will be determined from the difference between the 2008 and 2012 estimates. Plant biomass is approximately 50% carbon. Shrubs adjacent to the plot are measured, then cut down, dried and weighed.

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10

Carbon assessment in planted forests is also using a plot-based approach to estimate changes during CP1. The national plot measurement programme is currently limited to post-1989 forests (i.e. those covered by the Kyoto Protocol), but has the potential to incorporate the whole of the planted forest estate. For planted forests, the network of permanent plots used to provide an unbiased estimate of carbon stock change uses a finer subdivision (4 km2) of the national grid used for indigenous forests and shrublands. The finer subdivision is required because plantations tend to be less well distributed (i.e. more clumped) than indigenous forests and shrublands. The plot network was established in 2008, after forest owners lifted a ban on access for field measurement crews.

Figure 4: Layout of the cluster of four 0.04-ha (11.28-m radius) plots used to assess carbon stocks in planted forests. The field data required to estimate carbon stocks in planted forests are collected from a cluster of four 0.4ha circular plots at each site (Figure 4). Measurement protocols for above-ground carbon stocks are similar to those used in indigenous forests and shrublands. Some of the other carbon pools, however, present interesting

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challenges which require different measurement protocols. For example, carbon stocks in debris piles (e.g. windrows), where it is impossible to separate dead wood, litter and other extraneous material, are estimated from the shape and dimensions of the pile (Figure 5) and the ratio of wood volume to total pile volume (the packing ratio). Likewise recently thinned stands can contain large quantities of dead wood, which would be very time-consuming to measure using the indigenous forest and shrubland methodology. In this instance felled stems (termed ‘down trees’) are counted, and a sample measured as for live stems.

records. Carbon stock estimates are calculated by multiplying the area of each cell type by the soil carbon value for that type. Changes in carbon stocks, which at a decadal timescale are primarily driven by changes in land use (e.g. pasture → shrubland/forest and vice versa), are estimated by remapping the land use layer, and recalculating the carbon stock estimate.

Figure 6: Conceptual approach to estimating carbon stocks in New Zealand soils.

Conclusion

Figure 5: Generalised shapes used to estimate the gross volume of debris piles. For planted forests the field measurements provide inputs to a series of growth models which output estimates for each of the carbon pools and, where the complete stand tending regime is able to be specified, can provide a carbon yield table over the full stand rotation which predicts both past and future carbon stock changes.

Measuring carbon stocks in soils Estimating soil carbon requires a completely different approach. For Kyoto reporting purposes New Zealand has elected to use the IPCC-default methodology for determining steady state soil carbon stocks, customised for New Zealand conditions. This approach assumes that the quantity of carbon stored in the soil is the product of climate, soil type, topography and land use (usually measured as land cover). These variables are mapped at a national scale, and the maps overlaid to create a series of ‘cell types’, each of which is a unique combination of the four variables (Figure 6). Cell types are assigned an average soil carbon value from the National Soils Database and/or from additional sampling carried out to supplement the database

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This article provides but a brief overview of the methods being used to meet New Zealand’s requirements under the Kyoto Protocol to report on carbon stock changes in forests, shrublands and soils during CP1. Each of the methods has been fully documented and subject to international peer review. Readers wanting more detail are referred to the selected reading list, electronic copies of which can be requested by emailing the author. For further information contact: paytoni@landcareresearch.co.nz

Selected reading Baisden, W.T., Wilde, R.H., Arnold, G., & Trotter, C.M. (2006). Operating the New Zealand Soil Carbon Monitoring System. Landcare Research Contract Report LC0506/107 prepared for the Ministry for the Environment, Wellington. Coomes, D.A., Allen, R.B., Scott, N.A., Goulding, C., & Beets, P. (2002). Designing systems to monitor carbon stocks in forests and shrublands. Forest Ecology and Management, 164, 89-108. Davis, M., Wilde, H., Garrett, L., & Oliver, G. (2004). New Zealand Carbon Monitoring System: Soil data collection manual. Printed by the Caxton Press, Christchurch. Payton, I.J., Newell, C.L., & Beets, P.N. (2004). New Zealand Carbon Monitoring System: Indigenous forest and shrubland data collection manual. Printed by the Caxton Press, Christchurch. Payton, I.J., Moore, J.R., Burrows, L.E., Goulding, C.J., Beets, P.N., Dean, M.G., & Herries, D.L. 2007. New Zealand Carbon Monitoring System: Planted forest data collection manual. Version 2. Reports JNT0506/069 and NZCAS006/2007, prepared for the Ministry for the Environment, Wellington.


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Refining our understanding of the carbon cycle is an important stepping stone to improving prediction of future climate change. Drs Mike Harvey and Sara Mikaloff-Fletcher, National Institute of Water and Atmospheric Research (NIWA), explain: The Industrial Revolutions of the late eighteenth and early nineteenth centuries marked the start of the socioeconomic transition to the modern industrialised world that we know today. To power the revolution, mankind has harnessed the energy released in the combustion of fossil fuel. A product of this combustion has been the release of carbon into the atmosphere in the form of carbon dioxide. This carbon had previously been ‘locked away’ for millennia in fossil deposits. Building on this early industrial development, the global economy has continued to evolve with a dependency on fossil fuel energy and this shows a surprising predictable relationship (over many orders of magnitude) (Figure 1) for all nations, between the magnitude of the economy and the amount of fossil fuel combusted. To fuel economic growth, the demand for increased energy has been met relatively cheaply by burning more fossil fuel without accounting for the environmental consequences.

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million (ppm), and these levels are the highest that the atmosphere has experienced in the last 650,000 years, possibly the last 20 million years. In common with other monitoring sites around the world, the atmospheric record shows an exponential increase in atmospheric CO2 over the period of the record. The annual rate of increase is now exceeding 2 ppm per year. This increase in atmospheric CO2 is consistent with the increasing emission to the atmosphere of CO2 from the burning of fossil fuels. The above finding is supported by concurrent measurement at Baring Head of the isotopic forms of CO2 as well as other tracers. The fossil derived carbon has a distinctive source ‘signature’ of ancient plant material that has a relatively low abundance of carbon-13 and contains no carbon in the form of the rare radioactive isotope carbon-14. A further useful tracer of combustion is the oxygen to nitrogen ratio; the amount of this tracer is declining as the fossil CO2 is increasing. Through its radiative forcing, CO2 is the most important long-lived greenhouse gas of anthropogenic origin, responsible for more than 60% of enhanced greenhouse effect of the sum of the radiative forcing by all greenhouse gases of anthropogenic origin. Because of the complex nature of the Earth system, there is uncertainty around the sensitivity of climate to this forcing, i.e. the increase in temperature that will occur as a result of the enhanced greenhouse effect. There are lags in the system that mean that we are already committed to change in the century ahead. In spite of the uncertainty, there is a strong consensus that there is a very real risk of dangerous interference with the climate system if emissions remain unchecked. The United Nations Framework Convention on Climate Change (UNFCCC) has as its objective ‘stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.’

Figure 1: Comparison by Purchasing Power Parity of national Gross Domestic Product (Source: CIA World Factbook) versus national CO2 emission from fossil fuel combustion (Source: Carbon Dioxide Information Analysis Centre (CDIAC) for 2004). Each dot represents a nation. For clarity, a limited selection of nations is named.

What has been the cumulative effect on the atmosphere of fossil CO2 emissions?

The longest record of continuous CO2 concentration measurements in the Southern Hemisphere and secondlongest in the world is maintained at Baring Head, New Zealand (Figure 2) by NIWA. The longest is the well-known Mauna Loa record started 50 years ago by Charles D. Keeling. Recorded CO2 concentrations (Figure 3) have exceed 380 parts per

Figure 2: The cliff-top site of the Baring Head Station on the rugged South Coast of the North Island at the entrance to Wellington Harbour. The site is exposed to strong southerly winds and unpolluted air-masses originating to the south of New Zealand.

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The most recent assessment of the Intergovernmental Panel on Climate Change (IPCC) indicates the need for emissions to peak within the next few decades if we are to achieve the required stabilization. Thus ‘decarbonization’ of the global energy supply, and changing the economy/carbon relationship in Figure 1 is the major short-term challenge for the first half of the twenty-first century.

Figure 3: Increasing atmospheric carbon dioxide recorded in continuous measurements made at Baring Head since the 1970s. The light grey points show data in baseline conditions, the dark grey line is a smoothed series.

However, the atmospheric observations show that only about half of this (165 ± 4 Pg C) has accumulated in the atmosphere. This means that about half of the man-made emissions must have been taken up by the less wellunderstood natural components of the carbon budget: the land biosphere and the oceans. If it weren’t for these natural sinks, the concentration of CO2 would have already exceeded 450ppm, which is one of the target stabilization concentrations that has been proposed by some climate scientists and policy makers to prevent some of the more severe potential consequences of climate change. The natural sinks are clearly essential to balancing the carbon budget and meeting our stabilization targets, yet they are much more poorly understood than the fossil carbon emissions. An up-to-date collation of some of the best available data of the annual carbon budget and trends is made by the Global Carbon Project and available at: http://www. globalcarbonproject.org/carbontrends/ . The trend in the budget components is shown in Figure 4 and Figure 5. With increasing emission, there is some indication that the efficiency of the natural sink processes is declining slightly, which means that the airborne fraction could increase slightly.

What we know about the carbon cycle

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Along with the exponential increase in atmospheric CO2, the Baring Head record also shows a pronounced seasonal pattern, where atmospheric CO2 concentrations are higher in the spring and lower in the autumn. This seasonality occurs because of a strong natural cycle of atmospheric CO2, which is partly due to the land biosphere and partly due to the oceans. Plants take up a great deal of CO2 in the active growing season of spring and summer due to photosynthesis. During the winter, the amount of photosynthetic activity decreases, and the relative importance of biospheric emissions of CO2 is greater due to decomposition of leaf litter by microbes and respiration in soils. The ocean carbon cycle also has a strong seasonality, which is controlled by a combination of ocean physics, chemistry, and biology. The seasonality of northern hemisphere stations is much greater because of the greater landmass and consequently larger seasonal fluxes. The observational record of atmospheric CO2 has been, and will continue to be, invaluable as we advance our understanding of the carbon cycle. We need to understand the link between emission and anthropogenic carbon dioxide that remains in the atmosphere now and into the future if we are to be able to accurately predict the consequences of CO2 emission. Both quantities are very well-known, the former from global energy use databases, and the latter from the global network of atmospheric CO2 observing sites. The ratio is known as the ‘airborne fraction,’ and in recent decades this has remained relatively constant at around 55 to 60%. Why then, in the short-term, does only half of the emission remain in the atmosphere? Atmospheric CO2 can be thought of as having a budget, where the total amount of CO2 in the atmosphere reflects a combination of sources (processes that emit CO2 to the atmosphere) and sinks (processes that remove CO2 from the atmosphere). Based on economic data, population statistics, and energy use records, we know that human beings emitted about 244 ± 20 Pg C (1 Petagram of carbon = 1 billion metric tonnes of carbon) from fossil fuel burning and cement production between 1800 and 1994.

Figure 4: Trend in global anthropogenic carbon emissions (Source: www.globalcarbonproject.org).

Figure 5: The fate of anthropogenic carbon. Trend in key global carbon budget components (Source: www. globalcarbonproject.org)

Advancing understanding sinks processes through modelling Clearly, the global community needs to advance the understanding of natural sink processes. The natural sources and sinks of CO2 can be studied in two ways: from the ‘bottom up’ or the ‘top down.’ Bottom up studies use local or regional measurements of quantities that reflect carbon sources and sinks, which


questions. The strength of this feedback effect varies markedly amongst the current early generations of models. They will need to be refined and supported by increasingly sophisticated observational programmes.

Feedbacks or how sinks might change

Figure 6: Example of the gridded column average CO2 (parts per million) mole fraction calculated in CarbonTracker. Blue colours indicate regions where CO2 in the atmosphere is relatively low, whereas red colours indicate high CO2 abundances. Plumes of high concentration move with the weather systems across the continent and illustrate the dynamic nature of our atmosphere. These CarbonTracker results have been provided by NOAA ESRL, Boulder, Colorado, USA from the website at: http://www.esrl.noaa.gov/gmd/ccgg/ carbontracker/ .

An important area of carbon cycle uncertainty is the climate-carbon cycle feedbacks. A major concern is that as the globe warms, positive feedbacks could be invoked and these will result in reduction in the strength of the natural sinks. Several positive feedback mechanisms are known, some conflict and the combined effect of biological and physical processes is extremely complex and variable in time and space. As the ocean warms it is physically able to absorb less CO2, it may become stratified and so transfer of carbon to deep water is reduced. However, a recent study based on ocean model simulations and atmospheric CO2 observations suggests that climate change may have already increased wind-driven upwelling of carbon-rich waters in the Southern Ocean, which leads to a reduction in the Southern Ocean CO2 sink, an important sink region for the globe. In the land system, plant acclimation and other limiting factors may significantly limit the effectiveness of CO2 fertilisation (the increased efficiency of plant growth found experimentally at high CO2 levels). Climatic impacts such as drought, and the significant increase in respiration rate with temperature, may significantly increase net carbon emission. Complex models that couple the global climate system to the carbon cycle are needed to address these feedback

Research in New Zealand Beyond the important long-term records at Baring Head, there is a wide range of research in New Zealand that contributes to understanding of carbon cycling, both globally and regionally, in both marine and terrestrial environments. Data are set to increase as new measurement technologies that are able to make high quality observational data come on-stream. A new generation of satellite-borne observation will soon be operational through the Orbiting Carbon Observatory (NASA http://oco.jpl.nasa.gov) and the Greenhouse Gases Observing satellite (Japan http://www.gosat.nies. go.jp [choose English language option â&#x20AC;&#x201C; Ed] ). In addition, regional-scale modelling is advancing. NIWA is developing a new carbon model based on atmospheric inverse methods, which will also be expanded to include bottom up data from scientists studying the ocean and land carbon cycles from around New Zealand and Australia. This model is being developed in collaboration with partners at the National Atmospheric and Oceanic Administration in the United States, and will be based on the CarbonTracker model: http://www.esrl.noaa.gov/gmd/ccgg/carbontracker/.

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are then scaled up to cover larger areas and time periods, with models describing the source and sink processes. These approaches are complicated by the large variability of CO2 in space and time, which introduces a large amount of error in up-scaling observations. Furthermore, the net CO2 source or sink that we would like to measure is usually a relatively small difference between two much larger numbers. For example, the net oceanic CO2 uptake of 2.2 Pg C/yr reflects a difference between a total outgassing of about 90 Pg C/yr, and a total uptake of about 92 Pg C/yr. A similar situation exists in the land biosphere where natural sink uptake and source emission are around 120 Pg C/yr and net exchange is of the order of 1 to 2 Pg C/yr. The processes controlling these natural sources and sinks are highly complex and often poorly understood. Top down studies estimate regional sources and sinks from the time history of atmospheric CO2 concentrations from the global network of observing sites and an atmospheric transport model, which describes how emissions from a given region change atmospheric concentrations of CO2 at an observing station. This approach is often called inverse modelling, because the sources and sinks are inferred by backtracking from the final atmospheric distribution. Inverse modelling is strongly limited by the spatial coverage of the international observing network, which currently includes 89 sites to cover the global fluxes. This limitation is likely to disappear, however, with data assimilation from a new generation of satellites set for launch in 2009 that are able to map the global atmospheric column of CO2 down to the surface. In addition to data limitations, there are model limitations that are being worked on. Comparisons with aircraft data, for instance, have shown that biases in the model transport have a stronger impact on inversely estimated sources and sinks than previously thought. However, recent studies that used ocean interior observations of carbon and related tracers with atmospheric CO2 data in a joint ocean-atmosphere inversion have shown that these additional observations can help to overcome these challenges.

CarbonTracker has helped to develop a good understanding of carbon emissions globally (Figure 6) and in the continental U.S. with a relatively dense network of concentration observations. The project has developed powerful visualization tools, and is itself a useful resource for teaching on the carbon cycle. Regional studies have expanded to include Europe, Asia and now Australasia. By combining the results of this model with the process level understanding science colleagues working on bottom up studies, we will gain a deeper understanding of the carbon cycle in our region, the processes controlling it, and its climate feedbacks. For further information contact: m.harvey@niwa.co.nz

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terrestrial ecosystems – carbon sources or sinks? In this article David Whitehead, Adrian Walcroft, and John Hunt (Environmental physiologists in the Global Change Processes Team at Landcare Research, Lincoln and Palmerston North) and Craig Trotter (Senior technical advisor with the Ministry of Agriculture & Forestry, Wellington), explain why global warming is critically dependent on the delicate balance between uptake and loss of carbon in terrestrial ecosystems.

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Photosynthesis is the process used by plants to convert carbon dioxide from the atmosphere in the presence of light into carbon-based products. These assimilates are stored in plant parts and used to grow biomass. Carbon is also lost from plants by respiration that occurs in the light and the dark from leaves and woody components. For an ecosystem, carbon is added to the soil from dead leaves, woody components and roots. This is incorporated into the soil and is stored as organic matter but then decomposes, releasing carbon dioxide back into the atmosphere. For more than a century, research has focused on understanding the processes that regulate both photosynthesis and respiration. From the 1950s, this research was driven by the expectation that increased photosynthesis would lead to greater productivity in crop plants to provide more food for the world’s increasing population. More recently, the focus has changed to the role of terrestrial ecosystems, particularly forests, in regulating atmospheric carbon dioxide concentration and the implications for global warming and climate change. Forests are very important for sequestering carbon dioxide from the atmosphere, thus reducing the magnitude of the ‘greenhouse effect’ and slowing the rate of global warming. The scientific community now recognises that the dramatic increase in global temperature during the last century is attributable to increasing concentrations of greenhouse gases in the atmosphere, notably carbon dioxide from the increased burning of fossil fuels. While there is much technological research underway to replace the use of fossil fuels for energy production with renewable sources, to develop methods to capture carbon dioxide emissions from industrial processes and to reduce emissions of more potent greenhouse gases from farm animals, the only significant short-term solution to reducing greenhouse gas concentrations in the atmosphere at present is the removal and storage of carbon dioxide by terrestrial plants. The global importance of forests in sequestering carbon from the atmosphere to mitigate climate change and the emergence of international markets for trading carbon have highlighted the need to understand of the fate of carbon in ecosystems and improve estimated changes in carbon storage as forests grow. But, estimating the amounts of carbon stored in ecosystems and changes with time or with land use change is challenging for three main reasons.

Firstly, measurements of photosynthesis and respiration made on individual leaves are straightforward, but small errors in estimates for leaves lead to much larger errors in estimating canopy photosynthesis. Secondly, at the ecosystem scale, more than two-thirds of the carbon stored is in the soil. In fact, the amount of carbon stored in soil globally is equivalent to about 300 times the global carbon released each year from burning fossil fuels. The third reason is the difficulty in measuring carbon storage as it is the very small difference between large rates of uptake by photosynthesis and losses from respiration. These difficulties can only be overcome by using computer models that are based on knowing how photosynthesis and respiration processes work in plants and soils, and are capable of scaling up from measurements made on individual leaves or small plots of soil to whole ecosystems.

Measuring photosynthesis and respiration

Figure 1: View of the internal structure of a typical broadleaved plant, potato. The leaf was frozen in liquid nitrogen, fractured and photographed in a scanning electron microscope. Note the protective layer of epidermal cells on the upper surface of the leaf and the absence of stomata. On the lower epidermal surface, leaf hairs are present and stomata are clearly visible. Carbon dioxide from the atmosphere diffuses in through the stomata into the air cavities in the spongy mesophyll where the surface area of the cells is high, and dissolves in water. The carbon dioxide is then transported to the palisade mesophyll cells near the top surface of the leaf. These cells are packed full with chloroplasts and arranged tightly together to maximise the capture of light transmitted by the leaf. The chloroplasts are the sites of fixation where carbon dioxide is converted into sugars. Photosynthesis requires carbon dioxide to be transferred from the atmosphere to the sites of fixation by chloroplasts in cells in leaves. The concentration of carbon dioxide in the atmosphere is presently about 380ppm (parts of carbon dioxide per million parts of air, or 0.038%) and this diffuses into leaves, dissolves in water and is transported to the sites of fixation in the mesophyll cells in the leaf (Figure 1). The rate of carbon dioxide


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uptake is regulated by stomata on the surfaces of leaves (Figure 2) and the degree of opening is sensitive to light and humidity of the air, and less sensitive to temperature. The carbon dioxide concentration at the sites of fixation is close to zero ppm.

Using portable instrumentation that is readily available we are able to measure rates of photosynthesis for individual leaves in forest canopies (Figure 3). We then use canopy models that scale photosynthesis from leaves to whole canopies. This needs to be done carefully because the distribution of light and temperature through canopies and the responses of photosynthesis to environmental variables are non-linear. The most useful indicator of the performance of an ecosystem is its light use efficiency. This is calculated as the ratio of the net amount of carbon assimilated (photosynthesis minus respiration from leaves and woody components) and the amount of light absorbed by the leaves in a canopy. By expressing net carbon uptake in this way, we are able to compare rates from different ecosystem types (for example, pasture and forest) with different amounts of leaf area (for example, thinned and unthinned production forest stands) growing at sites with different amounts of annual incoming solar radiation (for example, Northland and Southland). As mentioned above, the largest component of respiration is from below-ground roots and organic matter in the soil, and rates of respiration are particularly sensitive to temperature. We are able to estimate rates of respiration at the soil surface from measurements of the rate of change of carbon dioxide concentration in small chambers placed on top of rings that are inserted to shallow depths in the soil (Figure 4).

Net ecosystem productivity The most reliable way we use to estimate net changes in carbon storage for a whole ecosystem is to measure changes in the uptake or loss of carbon for each component. We then sum these components and calculate total net loss or gain of carbon, known as the net ecosystem productivity. For a forest ecosystem, the components consist of carbon uptake from photosynthesis by leaves and carbon loss from respiration from leaves, stem, branches, roots and soil. Each component is sensitive to different

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Figure 2: View of a single stomatal pore taken from the lower surface of the leaf shown in Figure 1. Note the uneven thickening around the guard cells that enables the pore to be closed and opened with changes in hydrostatic pressure, and the subsidiary cells that make up the stomatal pore.

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Figure 3: Portable instrumentation used to measure photosynthesis and respiration of leaves. An attached leaf is placed in the chamber and the concentrations of carbon dioxide and water vapour are measured before entering and after leaving the chamber with infrared gas analysers, allowing calculations of stomatal conductance and photosynthesis rate. The light incident on the leaf is controlled with an artificial light source, and temperature and humidity within the chamber are also controlled.

Figure 4: Instrumentation for measuring rates of respiration from the soil surface. A small chamber is placed onto of rings set into the soil surface and, similar to the instrument shown in Figure 3, the rate of respiration is calculated from the difference in carbon dioxide concentration entering and leaving the chamber and the flow rate. Photograph courtesy of Cissy Pan.

environmental variables so, to estimate annual totals, we need to measure responses of photosynthesis to the intensity of sunlight, temperature and humidity and the response of respiration to temperature. Periodic drought also reduces rates of carbon uptake and loss. At Landcare Research, we have worked in a range of natural and managed ecosystems across New Zealand, but, as a case study, our recent focus has been on estimating net ecosystem productivity for a mature, rimu-dominated rainforest at Okarito, South Westland. This is the first time that direct measurements of carbon exchange have been made for this forest ecosystem, and our objective was to determine if mature lowland rainforests in New Zealand are a net source or sink for carbon.

From leaves to landscapes: a case study In the mature rimu rainforest, we undertook measurements of photosynthesis throughout the canopy and respiration of leaves, woody tissues and soil and used these with our canopy model to estimate annual carbon

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balance for the site. The data shown in Figure 5 illustrate the relative magnitude of the components.

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Figure 5: Components of net ecosystem productivity for the rimu-dominated mature rainforest at Okarito, South Westland. The components were calculated from measurements made using instrumentation shown in Figures 3 and 4, weather data measured above the canopy and a computer model. More details can be found at Whitehead et al. 2002. Analysis of the growth of rimu (Dacrydium cupressinum) in south Westland, New Zealand, using process-based simulation models. International Journal of Biometeorology, 46, 66-75. The two large components of the net ecosystem productivity are carbon uptake by photosynthesis, dominantly (87%) for the tree canopy and carbon loss by respiration, dominantly (60%) from soils. Over the whole year, we estimated that the ecosystem is losing a small amount of carbon because respiration losses exceed inputs from photosynthesis. The forest is near maturity and tree growth is very slow, but still positive. The large loss of carbon is clearly from the deep layers of organic matter accumulated over a period of 10,000 years at the site. Loss of carbon from soils by respiration is very sensitive to temperature. We are able to make direct measurements of the net exchange of carbon dioxide between whole ecosystems and the atmosphere using a micrometeorological technique called eddy covariance and this is employed widely by research groups worldwide. The measurements can be also be used to validate estimates of net carbon dioxide exchange from computer models, as we have done at our forest site at Okarito. The technique requires the use of a sophisticated sonic anemometer to measure wind speed in three dimensions very rapidly (about 10 Hz) and an analyser to measure carbon dioxide concentration. These instruments are located above the forest canopy (Figure 6) and the data recorded continuously. Knowing changes in carbon dioxide concentration and the direction of the wind allows calculation of the amount of carbon dioxide entering or leaving the ecosystem. These amounts can then be summed to give the net exchange over longer periods of time. The major lesson from our findings is that deep soils rich in organic matter in mature indigenous forests could increasingly become a major source of carbon dioxide as the Earthâ&#x20AC;&#x2122;s temperature increases, and this could lead to a positive feedback response that could accelerate global warming.

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Figure 6: Measurement of the net exchange of carbon dioxide between the canopy and the atmosphere for a mature rimu-dominated rainforest at Okarito, South Westland using the eddy covariance technique. The people are standing on a scaffold platform that is 25m above the forest floor and the instrumentation on the small tower is at a height of 32m. The sonic anemometer and instruments that measure weather variables are located on top of the small tower, and computers in the hut record and store the data. The solar panels provide power for the system to run. Photograph courtesy of John Byers.

Implications for New Zealand We have been able to demonstrate the usefulness of the approaches described above to calculate the first national estimate of carbon balance for the whole of New Zealand. Working at such large scales does require some simplification in the use of our models, but the detailed principles remain embedded in the calculations, providing a robust framework. There were five steps in our calculations: (1) We classified land use types of vegetation across New Zealand into six main types and used aerial mapping to estimate land areas associated with each land use. (2) We assigned a value for light use efficiency for each land use based on published data that included estimates from our own data and canopy models. (3) We used climate surfaces to estimate the annual incoming solar radiation and temperature at all sites on a grid across the country. This allowed us to calculate net primary productivity (carbon uptake from photosynthesis minus respiration from leaves and woody components) at each grid point across New Zealand. (4) Estimates of soil respiration were taken from our own data sets across a wide range of ecosystems. Subtracting this from net primary productivity allowed us to calculate


Land use Forest Indigenous Exotic Shrubland Grassland Improved Unimproved Tussock Total

Area Mha

Net primary productivity Tg C y-1 %

%

5.77 1.62 3.72

23 6 15

48 16 36

25 8 19

–8 5 –2

6.67 3.40 4.29

26 13 17

59 19 13

31 10 7

–6 3 7

191

–1

25.47

Net ecosystem productivity Tg C y-1

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Table 1. The national carbon balance for New Zealand, showing net primary productivity and net ecosystem productivity for the six land use types across New Zealand. These estimates do not include losses of carbon from erosion, but these amounts are not expected to be large. The quantities shown are annual amounts in Tg of carbon (= 1012 g).

More details can be found at: Trotter et al. 2004, A multi-scale analysis of a national terrestrial carbon budget and the effects of land use change in Global Environmental Change, in Ocean and on Land, Edited by M Shiyomi et al., pp. 311341. TERRAPUB, Japan.

net ecosystem productivity which represents net carbon uptake at each grid point. (5) These values were then summed across the grid to calculate net primary productivity and net ecosystem productivity for each land use type on a national basis. The data shown in Table 1 highlight the contributions of land use type to New Zealand’s national carbon balance. Net primary productivity is highest for improved grassland, then indigenous forest, but this is attributable to the large areas of land associated with these land uses. Exotic forest is more efficient at converting solar radiation into carbon as biomass than indigenous forest, but the land area for exotic forest is much less than that for indigenous forest. There is a large area of tussock grassland across New Zealand, but much of this is in dry or cooler regions where carbon uptake is low, so the contribution to national net carbon uptake is low. Annual net ecosystem productivity for indigenous forest (consistent with our findings at Okarito), shrubland and improved grassland is negative. The calculations show that, overall, New Zealand’s terrestrial ecosystems are close to being carbon neutral, with a net loss of about 1 Tg C year-1. If the emissions of carbon dioxide from burning fossil fuels (8.8 Tg C year-1) and cement production are included, then the carbon balance for New Zealand is estimated to be a loss of about 10 Tg C year-1. These calculations are important because they provide an estimate of net gains and losses of carbon at the national scale. This is required for New Zealand to meet its reporting requirements as a signatory to the United Nations Framework Convention on Climate Change (UNFCCC). The results also highlight the relative contribution of different land use types to sequestering carbon and the potential effects of changing land use

on national carbon storage. Lastly, and perhaps most important, our approach incorporates climate drivers in our models, so allows predictions of the effects of changes in climate at regional scales on national net carbon storage. In summary, the approach we have adopted to estimate carbon storage in New Zealand’s terrestrial ecosystems is based on a strong framework that describes the processes regulating carbon exchange for each component in the carbon balance for ecosystems. Measuring carbon storage at the national scale directly is challenging and requires considerable investment in resources (see Ian Payton’s article in this issue of the NZST, pp 16 to 18). Direct measurement of small changes in the large amounts of carbon stored in ecosystems is even more challenging. Our modelling approach has been validated at key sites and does allow estimates of changes with changing land use or climate to be made. Overall, our estimate of national carbon storage suggests that the terrestrial ecosystems of New Zealand are close to being carbon neutral. With predicted increases in temperature there is a strong possibility that our indigenous ecosystems will increasingly become sources, rather than sinks for carbon because of increased decomposition of soil organic matter. This could contribute to an accelerated rate of global warming, but could also be reversed by careful management and planning to favour land use options that sustain carbon storage. For further information contact: whiteheadD@landcareresearch.co.nz Acknowledgement: This work was funded by the Foundation for Research, Science and Technology.

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carbon in the stars Carbon is vital to life on Earth and yet we often neglect to query its source. C. Clare Worley, Mita Brierley and Karen Pollard, Department of Physics and Astronomy, University of Canterbury, give some stellar insights: “We are made of star stuff!” said Carl Sagan, the eminent astronomer and author. This is not something we usually consider as we go about our everyday lives and yet, without the stars, life as we know it would not have been possible. Humans are classified as carbon-based lifeforms. This means that the key atom necessary to our existence is carbon, and the only place the carbon atom can be made is in the stars!

Why is there carbon in the stars? The first stars in the Universe were made entirely of hydrogen and helium, because at that time, 13.5 billion years ago, that was all there was in the Universe. These stars formed from giant gas clouds composed of 75% hydrogen and 25% helium, and trace amounts of lithium. A typical star forming region, designated as NGC 3582, is shown in Figure 1.

Stellar Envelope: Hydrogen & Helium Gases Stellar Core: Hydrogen fusing into Helium

Figure 2a: A dwarf star, like our Sun, that burns hydrogen in its core to produce helium. is the ‘ash’ of hydrogen burning, will become the stellar fuel. The helium core will shrink so that the temperature increases to the higher levels needed for helium nuclear fusion to ignite. A star that is burning helium in its core is a red giant star as shown in Figure 2b. It takes a much shorter time for a star to burn its reservoirs of helium. Our Sun will spend only a few million years as a red giant. During this stage its surface will expand out past the orbit of Venus, Earth’s atmosphere will be boiled away and life as we know it will no longer exist. The red giant star, however, is the key stellar evolutionary stage for the creation of life, as the ash of helium nuclear fusion is carbon. Stellar Envelope: Hydrogen & Helium gas Nuclear burning Shell: Hydrogen fusing into Helium Non-burning Shell: Helium gas Stellar Core: Helium fusing into Carbon

Figure 1: NGC 3582 – a typical star forming region. Reproduced courtesy of National Optical Astronomy Observatory with credit and copyright to: T. A. Rector (U. Alaska), T. Abbott, NOAO, AURA, and NSF.

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Unlike NGC 3582, the very first gas clouds in the Universe had no pre-existing stars but were just a soup of hydrogen and helium atoms. Perturbations in these clouds caused dense pockets of gas to form, which increased gradually in temperature and pressure as more mass was accumulated. Eventually the temperature reached 8 million Kelvin, which is the temperature necessary for the ignition of hydrogen nuclear fusion. The pocket of highly dense gas became a hydrogen core undergoing nuclear fusion, surrounded by a hydrogen and helium envelope. This was how the first stars in the Universe were born. Figure 2a shows the internal makeup of a hydrogen burning star, or dwarf star. All stars are born, and spend the majority of their lives, as dwarf stars. Our Sun is a dwarf star so it is still burning hydrogen to helium in its core. However, it is not one of the first stars in the Universe as it was born only five billion years ago. Using up all the hydrogen in a stellar core takes a very long time. For example, it will take our Sun ten billion years in total to burn away all of its hydrogen. Once all the hydrogen in the core is used up, the helium, which

Figure 2b: A huge red giant star, into which our Sun will evolve, that burns helium in its core to produce carbon.

How is carbon made?

Figure 3: The triple-alpha process. Two helium atoms combine to produce a beryllium atom and pure energy in the form of a gamma ray. The beryllium atom then combines with a third helium atom to produce a carbon atom and more energy. Source: http://commons.wikimedia.org/wiki/File:Triple-Alpha_ Process.png


What does carbon do? As the first generation of stars began to die, the atoms they had created were expelled into the pristine gas clouds either explosively, as a massive star went supernova, or gently, as the atmosphere of a low mass star was puffed away in dying breaths. The next generations of stars formed from these now polluted gas clouds. Carbon, along with lots of other atoms, was already present in the gas cloud from which new stars, like our Sun, began to form. However, carbon is particularly important as it provides another means by which to fuse hydrogen atoms into helium atoms. This process, the CNO (carbon-nitrogen-oxygen) cycle, is shown in Figure 4.

Carbon stars tend to be red giant stars that are highly variable in brightness and are in the late stages of stellar evolution. The carbon observed in these stars has been formed through helium fusion in their cores, and brought up into the outer atmosphere by convection, where they form carbon monoxide (CO), molecular carbon (C2), cyanogen (CN), methane (CH4) and other carbon compounds. These stars are extremely red in appearance as their surfaces are very cool at 2000–3000K (hot stars are blue in appearance). Also the carbon dust in the atmosphere scatters and reflects the shorter (bluer) wavelengths of light further contributing to the apparent redness of the star. Another type of star for which carbon is important is the white dwarf. White dwarfs are the remnants of low to medium mass stars that became red giants in the final stages of their lives. They transform into white dwarfs by throwing off most of their outer atmosphere to expose hot stellar cores composed of carbon and oxygen, as shown in Figure 5. There is a residual atmosphere of hydrogen and helium but this dispels as the core gradually cools. Our Sun, like the majority of stars, will end its life as a white dwarf star.

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Carbon is the product of the nuclear fusion of helium atoms in what is called the triple-alpha process. Helium is referred to as an alpha particle, so in the triple-alpha process three helium atoms are needed in order to make one carbon atom as shown in Figure 3. These reactions occur in the core of a red giant star at a temperature of about 100 million Kelvin. There is no other environment in the Universe capable of this, which means that all of the carbon atoms that exist in us, in our planet and in our solar system were created in this stellar furnace.

The CNO cycle is much more complicated than the

Figure 5: The evolution of a red giant to a white dwarf. Drawn by Mita Brierley using images from the following sources: Picture 1: Andrea Dupree (Harvard-Smithsonian CfA); Ronald Gilliland (STScI); NASA; and ESA; Picture 2: Robert Rubin (NASA Ames Research Center); Reginald Dufour and Matt Browning (Rice University); Patrick Harrington (University of Maryland); and NASA; and Picture 3: NASA and The Hubble Heritage Team (STScI/AURA).

Figure 4: The CNO cycle. A complicated nuclear process which fuses hydrogen into helium using carbon, oxygen and nitrogen as catalysts. Source: http://commons.wikimedia.org/wiki/File:CNO_Cycle.svg

triple- alpha process. Using carbon, nitrogen and oxygen as catalysts, hydrogen atoms are converted into helium. The CNO cycle is the dominant hydrogen fusion process for stars of mass greater than 1.5 times the mass of the Sun. The discovery of this process was crucial, as it is the source of energy production in massive stars. The process was determined independently by two different researchers in the 1930s, one of whom, Hans Bethe, was awarded the Nobel Prize in Physics in 1967 “for his contributions to the theory of nuclear reactions, especially his discoveries concerning the energy production in stars.”

Are there stars made purely of carbon? Stars can contain differing amounts of carbon depending on factors such as their mass and their age. Most normal stars have more oxygen in their atmospheres than carbon, but there are some in which this ratio is reversed. These stars are called carbon stars, though they are still predominantly composed of hydrogen.

However, pure carbon stars do exist. In 2008, astronomers observed a new class of white dwarfs that are made purely of carbon. Prior to the white dwarf stage these stars are believed to have been massive stars that were not quite massive enough to explode as supernova. Instead they ejected their atmospheres, like lower mass stars, but left behind these pure carbon cores. White dwarf stars no longer undergo nuclear fusion, which is the source of the internal pressure that holds a ‘live’ star up against the force of gravity. The ‘dead’ star is crushed under its own weight until electron degeneracy pressure (caused by the inability of more than two electrons to share the same energy level around an atom – the Pauli Exclusion Principle) balances the gravitational compression. So these stars are extremely dense, with masses comparable to that of the Sun compressed into volumes similar to that of Earth. When they first form, white dwarfs are very hot (up to 150,000K), but they cool slowly over time. As they cool the plasma (a fluid of atoms and electrons) starts to crystallize, and as diamonds are just crystallized carbon, these stars in the end literally become “diamonds in the sky!”

Carbon between the stars: the interstellar medium Both carbon stars and the giant stars that become white dwarfs, lose large amounts of material into interstellar

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space. The material is expelled through powerful stellar winds and by dramatic stellar pulsations, forming glowing gas clouds around the star called planetary nebula like in Figure 5. The gas and dust eventually become part of the interstellar medium and, in places, condense into the massive gas clouds which are the sites for star formation as in Figure 1. In these stellar nurseries, the material thrown out by the old stars provides the ingredients used to form the next generation of stars and planetary systems. Indeed, systems such as our own solar system could not have formed without the pollution of the interstellar medium with heavy elements by earlier generations of stars. This evolutionary cycle of gas clouds and stars is illustrated in Figure 6. For humans as carbon-based life forms, the interstellar gas clouds in our Galaxy are especially important. Like the one from which our Sun and solar system were formed, the gas clouds contain the atoms necessary for the formation of organic molecules. These atoms are hydrogen, carbon, nitrogen, oxygen, sulphur and potassium, but carbon is the key, as it is the only atom that can bind to all the others to form the complex molecules that are necessary for life.

How much carbon is there? As carbon is so important in the development of life it might be assumed that large quantities of it are present in the Universe. Figure 7 shows the atomic composition of humans, the Earth’s crust, meteors in our solar system, the Sun and the Universe.

Figure 7: Percentage of atoms, in terms of mass, for humans, the Earth’s crust, meteors, the Sun, and the Universe. Key atoms, such as hydrogen and carbon, are noted for each. Image created by Clare Worley, data sourced from: http://www. periodictable.com

Figure 6. The evolutionary cycle of gas clouds to stars to gas clouds, and the different types of stellar death for different mass stars. Image courtesy of Mita Brierly, data from: http://www.strw.leidenuniv.nl/~woitke/Bilder/Cycle_of_matter_small.jpg

Indeed, quite complex organic molecules, such as HC11N, and pre-biotic molecules such as H2CO have been detected in interstellar clouds. For instance in the star forming region NGC 3582 (Figure 1) astronomers have detected the presence of the complex carbon molecules known as polycyclic aromatic hydrocarbons (PAHs). These molecules are formed in the cooling gas of star forming regions, and their development in the cloud from which our Sun formed about five billion years ago may have been crucial in the development of life on Earth.

Does carbon mean life?

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Astronomers using the Hubble Space Telescope have recently discovered carbon dioxide on the extra-solar planet, HD189733b. This gas giant planet is too hot for life to survive, but the discovery shows that current technology is capable of detecting the building blocks necessary for life in the atmospheres of distant planets. Water vapour, methane and carbon monoxide have also been discovered in the atmosphere of this planet, but the carbon dioxide is of particular interest because on Earth it is linked to biological activity. The presence of organic compounds is not necessarily an indicator of life on extra-solar planets, but they can be the by-products of life processes. Future observations under the right conditions, such as around a rocky, Earth-like planet, could provide the first evidence of extra-terrestrial life.

Clearly carbon is a major ingredient in humans, at 23% of the mass, but it is only 0.2% of the mass of the Earth’s crust; 1.5% of the mass in meteors; 0.5% the mass of the Sun; and only 0.3% of the mass of the Universe as a whole. As expected, hydrogen and helium dominate the mass of the Sun and the Universe at 75% and 23% respectively, but even with all the billions of stars in the galaxy, the percentage of all the other atoms has increased from ~0% at the beginning of time to only 2% of the total mass a mere 13.5 billion years later. So while humans may be representative of the atomic ingredients necessary for life, they are not indicative of the main ingredients of the Universe.

Conclusion In a self-perpetuating stellar factory, new stars are forming from the dust of old stars. Within these stars the primordial atoms of hydrogen and helium are being converted ever so gradually into heavier atoms, and these heavier atoms are doing amazing things. In particular they are responsible for creating life. Despite its rarity in the Universe, carbon was crucial in the development of life on Earth and astronomers are finding more and more evidence of the potential for life outside our solar system in the form of simple and complex carbon molecules. Ultimately carbon is star dust, created in the fiery core of a red giant star, and while humans are not solely made from carbon, it can be said that we are definitely made of “star stuff!” For further information contact: clare.worley@pg.canterbury.ac.nz

Resources Ingredients for Life: Carbon http://www.teachersdomain.org/resource/ess05.sci.ess.eiu.carbon/ Hydrogen & Helium Burning in Stars: http://www.mpg.de/english/illustrationsDocumentation/multimedia/ mpResearch/2008/heft02/010/index.html Pure Carbon Stars: http://www.universetoday.com/2007/11/26/purecarbon-stars-discovered) PAHs: http://www.astronet.ru/db/xware/msg/1227513 Carbon dioxide found on extrasolar planet: http://www.astronomy.com/asy/default.aspx?c=a&id=7724


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Written by Miles Barker, University ofWaikato

About eight years ago, Mary Loveless and I wrote a paper (Loveless and Barker, 2000) entitled: ‘Those pages we just turn over …: The ‘nature of science’ in Science in the New Zealand Curriculum.’ You will recall that in our previous (1993–2007) – now superseded – science curriculum document (Ministry of Education, 1993b), achievement objectives concerning the ‘nature of science’ were contained in an integrating strand (pages 24-41) that preceded the content-laden contextual strands (pages 52–123). As the title of our paper suggested, our initial hunch was right: the ten interviewed teachers were very diffident about teaching the ‘nature of science’ and for most of them the integrating strand comprised “those pages we just turn over …” How has this changed now that we have a new science curriculum, contained within a single jumbo document for all curricula, namely The New Zealand Curriculum (Ministry of Education, 2007)? At least there is one decisive change: teachers of science can now no longer literally “just turn over” the pages devoted to the ‘nature of science’ because, in the new curriculum – apart from some introductory material (page 28) – the ‘nature of science’ is addressed on each of the eight pages of the science content. Now, however, I have another hunch. It concerns the four generic, framework-type sections (‘Visions,’ ‘Principles,’ ‘Values,’ and ‘Key Competencies’) of The New Zealand Curriculum (i.e. pages 8-13) that I know many of the curriculum developers viewed as the most pivotal aspects of The New Zealand Curriculum. My new hunch is driven in part by Baker’s (1999) evidence that teachers of science, by and large, paid little attention to the previous overarching material, i.e. ‘The Essential Skills,’ ‘Attitudes and Values,’ etc. in the separate New Zealand Curriculum Framework (Ministry of Education, 1993a). My new question takes this form: To what extent will teachers of science now “just turn over” the pages on ‘Vision,’ ‘Principles,’ ‘Values’ and ‘Key Competencies’ in The New Zealand Curriculum? For the previous curriculum, Mary and I attributed science teachers’ page turning to the perceived vagueness and irrelevance of the ‘nature of science’ material. Now, I suspect that there is a new need amongst science educators for elucidation and for help with forging of intra-curricular connections. Two general issues emerge: ‘How can the generic aspects of The New Zealand Curriculum, the ‘Vision,’ ‘Principles,’ ‘Values’ and ‘Key Competencies’ inform, enliven and focus science education?’ and ‘How can science education, in pursuing its own purposes, simultaneously contribute to the development of the four generic aspects of The New Zealand Curriculum?’ Before I discuss this in more detail, I would like to briefly recap some of my experiences of the process by which The New Zealand Curriculum was generated.

From 2002 to 2006 From 2002 to 2006 there was the development of ‘The New Zealand Curriculum Draft for Consultation

2006.’ Most of us will recall that the process began with our initial Curriculum Review (2000-2002), which culminated in the production of the Curriculum Stocktake Report (Ministry of Education, 2002), with its 43 recommendations. This was followed by the setting up of numerous working parties, charged with developing these recommendations. Early on, in the science area, I noticed a feature that surprised me: the revision process appeared to be focussing on stocktake recommendation 282 (“…the number of strands and objectives specified at each level should be reviewed”) and a reduction in the number of achievement objectives had emerged as its major goal. My personal concern was: would a curriculum, the devising of which has a goal of simplification, adequately reflect a future world undoubtedly to be characterised by “super complexity” (Barnett, 2004)? But soon it became clear that the course of the whole project was changing. As my friend and colleague at the University of Waikato, Paul Keown, who was working in the social studies area, put it: “The Ministry’s initial quite single-minded focus in Learning Area working parties on reduction in the number of achievement objectives was gradually subsumed as other stakeholders brought their concerns to bear on the process.” Four of these subsequent developments were: • the enrichment of ‘skills’ (recommendation 276) into ‘key competencies.’ This was evident from 2004 onwards • a reconceptualisation of ‘values’ (273) in our education system. Paul, himself, came to head a new working party in this area • developing approaches to assessment, including NCEA (292) that are more supportive of (or less antagonistic to) the wider intentions of this new curriculum • the maintaining of the six future-focussed curriculum themes (278) as a presence in the new curriculum. Around 2004-2005, these appeared to me to be in danger of disappearing altogether. However, lobbyists for environmental education (who were especially keen on the notion of ‘sustainability’) and others, ensured that they persisted. The Draft contained five such “themes” (Ministry of Education, 2006, p.26) and The New Zealand Curriculum contains four “futurefocussed issues” (Ministry of Education, 2007, p.39).

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2007 and beyond In this section I shall attempt to open up some challenges that, I believe, The New Zealand Curriculum poses for us science teachers. I shall not attempt to critique the science content (‘Living World’ etc.) at each of the eight levels – it is the most recognisable feature to survive from Science in the New Zealand Curriculum (Ministry of Education, 1993b) – and my treatment of the ‘nature of science’ (on each of these eight pages) will be less than it deserves. Rather, I shall concentrate on our science education stance towards the four generic aspects of the whole curriculum.

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Vision, page 8. It is important to understand that this comprises a definition of the desired characteristics for our young people: namely that they be confident, connected, actively involved lifelong learners. How does this resonate, if at all, with science education? I would like to approach this question by thinking about two young science learners I know. From time to time I visit Robbie, who is five years old, and his brother Charles, who is aged six. They know I’m interested in things to do with science, and they have a little red box in their living room into which they put ‘Questions for Miles’ that interest them. Here are four of them: Robbie: “Why do babies love formula and kids hate it?” (Robbie’s one-year-old sister drinks formula milk from her bottle). Charles: “Why are there green ladybirds and red ladybirds?” (Charles likes wandering around gardens with a magnifying glass). Robbie: “How are hills made AND I DON’T MEAN VOLCANOES?” (Robbie lives near an urban volcano but he also often journeys by car across rural landscapes). Charles: “Why do you cry salty tears when you stub your toe?” (Charles had apparently just interacted with a piece of furniture). These questions clearly ramify across the content of many branches of science, and far beyond science; they contain springboards for sophisticated later science learning, and in their elucidation they are already beginning to probe the nature of science itself. It is probably fair to say that Robbie and Charles can currently be described as ‘confident,’ ‘connected’ and ‘actively involved’ learners; the most problematic aspect appears to be whether their motivation will be ‘lifelong.’ Worldwide, learner motivation in science education is singularly under-researched. Massive surveys of science education often accord motivation relatively little attention (for example, Abell and Lederman, 2007, p. 85-93) and those who work creatively in the field, for example, Norway’s Svein Sjoberg (Tobin and Roth, 2007, p. 95-106) are few. It seems to me that enhancing the resonance between science education and the ‘Vision’ statement in The New Zealand Curriculum could well be informed by a focus on this question: What forms of science education in New Zealand (topic choices, purposes, teaching styles, timetabling, meaningfulness, relevance, etc.) are most likely to motivate young people to be confident, connected, actively involved lifelong learners? It also occurs to me that underpinning this question are two issues for learners which, in their quasi-psychological and quasi-spiritual nature (and, yes, their visionary nature) are questions that we have traditionally not focused on as science educators, namely: What kind of person do you want to be? What kind of world do you want to live in? Principles, page 9. By contrast with the ‘Vision,’ the ‘Principles’ concern the decision making processes (planning, prioritising) by which curriculum is formalised in schools. Here, then, we need to look at how science education is actually being put into practice in our school classrooms, and to consider as a very relevant question: Which emerging trends in science education in New Zealand might resonate especially strongly with the eight ‘Principles’ namely: high expectations; Treaty of Waitangi; cultural diversity; inclusion; learning to learn; community engagement; coherence; and future focus? I suggest that the amplification of three current trends in New Zealand – the teaching of science from socioscientific issues; our developing notions of socio-cultural

classroom learning; and a more integrated approach to science learning – could be especially fruitful in highlighting the ‘Principles.’ Firstly, the focus on socio-scientific issues, as now required in the innovative ‘Nature of science: participating and contributing’ material across the eight levels of the science Learning Area, would seem to map especially strongly on to the ‘Principles’ of community engagement and future focus. Teaching science from, or with, issues beyond the classroom currently receives variable exposure worldwide. Less venturesome interpretations relate to museum visits and the like (Rennie, 2007), and to the documentation of environmental attitudes and knowledge in a science context (Barker, 2004). More expansive approaches (e.g. Levinson, 2006; Oulton et al., 2004) address how science teaching and learning can actually engage systematically with community and global issues such as ‘Genetic Engineering’ or ‘Aids.’ Examples of studies carried out in New Zealand, where science teaching and learning now has a curriculum mandate at levels five and six to “…take action where appropriate,” are Conner (2003) and Jones et al. (2007). There is, of course, considerable overlap between science education and environmental education in their respective approaches to socioscientific issues. This has been explored in New Zealand, both from the point of view of science education (Hipkins et al., 2002, pp. 225-228) and environmental education (Cowie et al., 2004). Secondly, the notion of socio-cultural learning, which increasingly underpins much thinking about science education in New Zealand, would seem to significantly collaborate with the three ‘Principles’ of Treaty of Waitangi, cultural diversity and inclusion. Socio-cultural learning theory is now advocated worldwide in a crosscurricula sense (Barker, 2007, pp. 31-33), including science education (Bell, 2005, pp. 43-52), and it is becoming increasingly prominent in science education in New Zealand (Hipkins et al., 2002, pp. 129-138). In New Zealand, socio-cultural approaches to learning in science, with their emphasis on the negotiation of cultural borders, underpin both Kaupapa Maaori pedagogy and the teaching of science in multicultural classrooms (Hipkins et al., 2002, pp. 201-213). As well as the way in which the fostering of inclusive science learning communities, comprising culturally diverse learners, can be a powerful, if general, vehicle for enhancing these four ‘Principles,’ there may also be another more sharply focused, knowledge-based contribution which science education can make. In requiring (‘Nature of Science: understanding about science’) students to explore the characteristics of science knowledge at large (its purposes, limits, development, etc.), the science curriculum now becomes a significant context for a richer and crucial appreciation of the characteristics of the knowledge systems of cultures owned by ourselves and others (Hipkins et al. 2002, pp. 205-205). Thirdly, the notion of integrated science learning would seem to contribute strongly to the ‘Principle’ of coherence and be encouraged by it. However, ‘integrated science learning’ has many meanings in New Zealand (Hipkins et al., 2002, pp. 216–225). Especially in primary schools, it can refer to thematic units where the teacher takes a topic (e.g. ‘Spring’) that is explored through the lenses of various curriculum Learning Areas, for example, in science, finding out how the seasons actually originate. In secondary schools, science integration is more likely to be based on an issue of concern introduced by the teacher or the students in a science learning context, the exploration of which ramifies into social, health


and in our science education in particular, it is timely to ask: What is the relationship between the five generic key competencies (thinking; using language, symbols and texts; managing self; relating to others; participating and contributing) and the capabilities that are prescribed at the eight levels of the science curriculum? Although Barker, Hipkins and Bartholomew (2004) argued well prior to the publication of The New Zealand Curriculum that “it is essential to define science competencies (at the level of the New Zealand science curriculum) which can be clearly seen to resonate with the (Key) competencies (at the curriculum framework level)” this resonance is, in my view, currently far from clear. There are some clues: the rubric ‘participating and contributing’ occurs both as a key competency and a section of the ‘Nature of science’ strand; ‘using language, symbols and texts’ as a key competency apparently has a parallel in ‘Communicating in science’; and the key competency ‘thinking’ has obvious (if often tacitly stated) resonances with the science curriculum content, with the stated processes of school science, and with ‘understanding about science.’ However, I am of the view that at least three crucial, issues exist for us: Definition: How do we teachers of science construe what a ‘competency’ actually is?2 What do we make of the notion that competencies are “more complex than skills” (The New Zealand Curriculum, p.12)? Do we apprehend that competencies subsume knowledge (and skills, and attitudes, and values) and are meaningful only in the knowledge-laden challenges which real-world tasks present? Relevance: Do we teachers of science consider that all five key competencies are centrally and equally relevant in science education? More specifically, how pervasive is the view that doing mature school science is fundamentally about ‘thinking’ processes, peripherally supported by a cluster of juvenile socialising prerequisites like ‘relating to others’ and ‘managing self’? Assessment: How are the five key competencies to be assessed in the context of science education?

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and environmental aspects. ‘Integration’ in this sense is pursued through the socio-scientific issues discussed above. Values, page 10. ‘Values’ receives far more prominence in The New Zealand Curriculum than previously. According to Keown (2001), the New Zealand Curriculum Framework (Ministry of Education, 1993a) contained “worthy goals in broad general terms” which, however, were “not developed in enough detail to provide curriculum writers and teachers with enough background or advice to actually achieve these intentions,” According to a ranking system devised by Keown (2001), Science in the New Zealand Curriculum contained only very modest treatment of values, and this appears to have been reflected in classroom practice (Barker, 2001). Given this situation, I suggest that a highly relevant question for us is: In what ways can teaching and learning in science education contribute to values’ education in New Zealand and be informed by it? Finding out what teachers of science understand what values’ education actually is would be a valuable beginning. The New Zealand Curriculum makes it clear that values’ education as it applies to science education, would need to be much wider than the observing of animal ethics. The New Zealand Curriculum takes the view that, far from being an opportunity to exhort students to adopt or manifest certain virtues, values’ education is a sophisticated critical exercise in enquiry, negotiation and reflection. I suggest that we teachers of science may have lots of thinking and talking to do about some basic issues before big changes occur in our teaching. For a start, how comfortable are we with McMullin’s (2000, p. 550) claim that, in contrast with one hundred years ago when science was generally considered to be ‘value-free,’“the maxim that scientific knowledge is ‘value-laden’ seems (now) almost as entrenched as its opposite was earlier”? Would we go further and, with Putnam (2004), reject the notion that value judgements are outside the sphere of reason, and that a strict fact/value dichotomy in science is no longer tenable? Do we think that there is a viable distinction to be made between values that are internal (i.e. epistemic) to the science enterprise, and values in society at large (Ruse, 1999, p.32)? Which values do we see as being strongly exported and imported between the science enterprise and society at large (Allchin, 1998)? Our answers to this last question might bring us back to my overarching theme in this article: are there, therefore, certain values to be developed in science education which might contribute especially strongly to the seven values listed in The New Zealand Curriculum page 10, namely, ‘excellence’; ‘innovation, inquiry and curiosity’; ‘diversity’ etc.? I suggest that even the most internalist, partitioned view of professional science might allow that ‘integrity’ with regard to scientific evidence – scientists often refer to this as ‘objectivity’ (Ruse, 1999) – is at the very core of professional science, and that this value is one which science inevitably contributes significantly and desirably to society at large. Other values contenders for targeted focus in science lessons might be ‘community and participation’ for the common good (if we consider societal uses and misuses of science), linking strongly to ecological sustainability, and across to ‘innovation, inquiry and curiosity,’ if we recall the creative, wonder-filled experiences which science can almost uniquely afford (Milne, 2008). Finally, such a targeted treatment of values as this would, of course, illuminate how we might more richly and fruitfully address the ‘Nature of Science: understandings about science.’ Key Competencies, page 12. Given that ‘competencies’ is a novel notion both in New Zealand education generally1,

A final word I am sure that there would be (and should be) as many ways of identifying linkages of ‘vision,’ ‘principles,’ ‘values’ and ‘key competencies’ between the framework level and the science curriculum level in The New Zealand Curriculum as there are individual teachers of science. The debates and the research that ensues will be fascinating. However, I do hold that if we teachers of science seriously espouse the value of integrated curriculum teaching, and if we really do wish to encourage a deeper focus on what it actually means to be a learner in New Zealand today, then we must address these issues in a concerted way. The alternative is regard the ‘vision,’ ‘principles,’ ‘values’ and ‘key competencies’ statements as merely “…those pages we just turn over.” For further information: mbarker@waikato.ac.nz

Notes: The notion of competencies does have an international history, however, going back twenty years (Reid, 2006). 2 The definition, adopted by Brewerton (2004) from the Defining and Selecting Key Competencies (DeSeCo) Project, was: “Competencies are integrated, holistic and complex: they include the knowledge, skills, attitudes and values needed to meet the demands of a task.” Commentary on the development of New Zealand’s Key Competencies is provided by Rutherford (2005). 1

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time to bring science alive Is science losing favour among school children? Ian Milne, coordinator of the NZASE primary science education support group, writes: It is not surprising that the 2007 National Education Monitoring Project, or NEMP, results identified a substantial increase in Year 8 students’ dislike for the science education they are doing at school. It mirrors worldwide trends. There have been repeated concerns expressed about the negative attitudes towards school science that normally start appearing in students at secondary school age, but are now being expressed by Years 5 and 6 students. Of concern to science educators is that research shows many examples of children who expressed negative attitudes towards school science and continuing their studies in science still believe science is important and of value to them and to society in general. This decline in positive attitudes towards school science activity is mirrored by an ever increasing loss of status of science teaching and learning in an overcrowded primary curriculum. Not many years ago, science, mathematics and English were identified as core subjects, the cornerstones of a modern educational curriculum. Unfortunately for science, the demands of what could be labelled a ‘back to the basic movement’ encompassed in the numeracy and literacy projects have captured significant amounts of the school day. In many schools, science has been reduced to being part of topic studies, integrated with social studies, health and technology, often losing its identity in the process. This leads to children listening and writing about science phenomena, rather than exploring and investigating everyday materials and equipment. The pressure of time constraints imposed by the crowded curriculum is increased further when schools buy into one of the ever increasing learning focuses in the form of ‘habits of mind,’ ‘thinking hats’ and ‘inquiry learning.’ Whilst there are compelling reasons for the inclusion of all three of these processes in the primary curriculum, it should be recognised that the processes of doing science – that is: exploring, questioning, explaining, testing and sharing our thinking – encompasses many of the elements that make up these processes. It appears that schools are developing their own school-based inquiry processes as a way of obtaining curriculum coverage. In reality, the learners are often only becoming skilled at literacy resource-based inquiry. This is often based around generic fertile questions with predetermined teacher-selected outcomes. It should be noted that some schools have recognised the potential of science to provide their students with rich learning experiences. Phenomena is explored, authentic investigations are planned, carried out and reported on. The children’s curiosity drives the investigative process. They get to wonder what will

happen when, or they get to wonder why. Surely these are the types of attitudes that science inquiry should be fostering in the primary curriculum. Unfortunately, there are no explicit references in the new curriculum that promote the development of affective attitudes like curiosity, awe, wonder, and interest as a goal of science. This is despite significant claims worldwide from science educators for the inclusion of goals in science education that promote children’s natural curiosity and desire to explain and understand the natural environment. During the consultation phase of the draft curriculum, the Royal Society of New Zealand (RSNZ) and the New Zealand Association of Science Educators (NZASE) strongly urged the writing group to make the importance of the affective domain in science more explicit. Not withstanding this lack of affective influence, the new science curriculum emphasis on scientific literacy is very evident in the overarching nature of science strands. In particular the reference to investigative learning outcomes like “extend their experiences and personal explanations of the natural world through exploration, play, asking questions and discussing simple models” should signal to teachers that asking children to do science will often require hands-on practical experiences or high quality visual and physical resources. If primary schoolchildren do get to do science as suggested above, then Paul Callaghan’s plea that teachers should “Put the play back into the primary school classroom” will eventuate. But more exploration and play in primary science lessons requires both financial and professional development support for teachers. It will require the Ministry of Education and other educational agencies to work together to support schools and teachers who are motivated to develop more engaging learning activities in primary science. Groups like RSNZ and NZASE have to continue to be proactive in the promotion of science education in primary schools. Principals will need to show curriculum leadership and become informed about primary science, and value the teachers who lead their science teams by making them resource teachers of science and formally rewarding their work by allocating them a management unit. Principals also need to acknowledge science as an integral aspect of the school curriculum that can provide rich and authentic contexts for using literacy and numeracy knowledge and skills. They will be able to justifiably allocate time in mathematics and literacy programmes for science. Using science as an authentic context for the learning about using statistics would be a useful starting point. It may be useful to look to the UK and Australia where approaches have been developed that focus on enhancing primary students’ engagement in science. Primary Connections, which focuses on links between literacy and science and Spellbound Science, involving stories about puppets solving science problems, are two recent resources that we could learn from.


References

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Abell, S., & Lederman, N. (2007). (Eds.). Handbook of research on science education. Mahwah, NJ: Lawrence Erlbaum. Allchin, D. (1998). Values in science and science education. In B. Fraser & K. Tobin, International handbook of science education (pp.1083-1092). Dortrecht: Kluwer Academic Publishers. Baker, R. (1999). Teachers’ views: ‘Science in the New Zealand Curriculum’ and related matters. New Zealand Science Teacher, 91, 3-16. Barker, M. (2001). Learning for the environment – how can science educators contribute? New Zealand Science Teacher, 97, 7-13. Barker, M. (2007). How do people learn? Understanding the learning process. In C. McGee, & D. Fraser (Eds.), The professional practice of teaching (pp. 1748). Melbourne: Cengage Learning. Barker, M., Hipkins, R., & Bartholomew, R. (2004). Reframing the essential skills: implications for and from the science curriculum. A commissioned research report for the Ministry of Education, Wellington, New Zealand, July 2004. Barker, S. (2004). Science and environmental education. In E. Scanlon, P. Murphy, J. Thomas, & E. Whitelegg (Eds.), Reconsidering science learning (pp. 250-262). London: RoutledgeFalmer. Barnett, R. (2004). Learning for an unknown future. Higher Education Research and Development, 23(3), 247-260. Bell, B. (2005). Leaning in science: the Waikato research. London: RoutledgeFalmer. Brewerton, M. (2004). Reframing the essential skills: implications of the OECD Defining and Selecting Key Competencies Project. A background paper for the Ministry of Education. Wellington: Ministry of Education. Conner, L. (2003). The importance of developing critical thinking in issues education. New Zealand Biotechnology Association Journal, 56, 58-71. Cowie, B., Eames, C., Harlow, A., & Bolstad, R. with Barker, M., Keown, P., & Edwards, R. (2004). Environmental education in New Zealand schools: research into current practice and future possibilities. Volume 3: A critical stocktake of the characteristics of effective practice in environmental education in New Zealand schools and kura kaupapa Maori. Wellington: Ministry of Education. Hipkins, R., Bolstad, R., Baker, R., Jones, A., Barker, M., Bell, B., Coll, R., Cooper, B., Forret, M., Harlow, A., & Taylor, I., France, B., & Haigh, M. (2002), Curriculum, learning and effective pedagogy: A literature review in science education. A review commissioned by the Ministry of Education, Wellington, New Zealand.

Parents and families can then be invited to school to see and hear about the children’s successes in exploring phenomena, asking questions, planning and finding answers to their questions and sharing the process. However, it will be essential for schools doing this to engage with the expertise within the wider community as well as taking advantage of the many science outreach programmes and events that are available. Where possible introduce your students to scientists and their work. The new Science Learning Hub being developed may provide further leadership with this aspect. It is important that teachers and other adults working with children think about their own childhood science experiences and reunite themselves with their own childhood memories as they explored and made sense of their world. In doing so it may assist them to protect and enhance in the children what Rachel Carson refers to in the following quote as their “inborn sense of wonder:” “A child’s world is fresh and new and beautiful, full of wonder and excitement. It is our misfortune that for most of us the clear-eyed vision, that true instinct for what is beautiful and awe-inspiring, is dimmed and even lost before we reached adulthood. If I had influence with the good fairy who is supposed to preside over the christening of all children I should ask that her gift to each child in the world be a sense of wonder so indestructible that it would last throughout life, as an unfailing antidote against boredom and disenchantments of later years, the sterile preoccupation with things that are artificial, the alienation from the sources of our strength.” If this is achieved then maybe we will start reducing the negative results that NEMP 2007 has identified. For further information contact: i.milne@auckland.ac.nz This article was also published in Educational Review, Vol 13 no 38, October 10, 2008, page 7 – Ed. Jones, A., McKim, A., Reiss, M., Ryan, B., Buntting, C., Saunders, K., & Conner, L. (2007). Research and development of classroom based resources for bioethics education in New Zealand. Report to Toi te Taiao: the Bioethics Council, 161 pages. December, 2007. Keown, P. (2001). Values and citizenship in the New Zealand curriculum: an analysis. Paper presented at the Pacific Circle Consortium 25th Annual Conference, Christchurch, 27th September. Levinson, R. (2006). Towards a theoretical framework for teaching controversial socio-scientific issues. International Journal of Science Education, 28(10), 1201-1224. Loveless, M., & Barker, M. (2000). “Those pages we just turn over ...”: The ‘nature of science’ in Science in the New Zealand Curriculum. New Zealand Science Teacher, 93, 28-32. McMullin, E. (2000). Values in science. In W. H. Newton-Smith (Ed.), A companion to the philosophy of science (pp. 550-560). Malden, MA: Blackwell. Milne, I. (2008). Creativity in the science classroom. New Zealand Science Teacher, 117, 45. Ministry of Education (1993a). The New Zealand curriculum framework. Wellington: Learning Media. Ministry of Education (1993b). Science in the New Zealand curriculum. Wellington: Learning Media. Ministry of Education (2002). Curriculum stocktake report. Wellington: Ministry of Education. Ministry of Education (2006). The New Zealand curriculum – draft for consultation 2006. Wellington: Learning Media. Ministry of Education (2007). The New Zealand Curriculum. Wellington: Learning Media. Oulton, C., Dillon, J., & Grace, M. (2004). Reconceptualising the teaching of controversial issues. International Journal of Science Education, 26(4), 411-423. Putnam, H. (2004). The collapse of the fact/value dichotomy. Cambridge, MA: Harvard University Press. Reid, A. (2006). Key competencies: A new way forward or more of the same? Curriculum Matters, 2, 43-62. Rennie, L. (2007). Learning science outside of school. In S. Abell, & N. Lederman (Eds.), Handbook of research on science education (pp. 125-170). Mahwah, `NJ: Lawrence Erlbaum. Ruse, M. (1999). Mystery of mysteries: is evolution a social construction? Cambridge, MA: Harvard University Press. Rutherford, J. (2005). Key competencies in the New Zealand curriculum development through consultation. Curriculum Matters, 1, 210-227. Tobin, K., & Roth, W.-M. (2007). The culture of science education: Its history in person. Rotterdam: Sense Publishers.

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Overall, a more imaginative approach that mixes traditional ideas with the new may be necessary to overcome the aspects of current practice that turn students off science. Do we need every child to write up a record of what they have done and what process they did? Why must every exciting and interesting event that may only last a few moments be followed by a long period of recording and reporting? Instead, there should be lots of exploring with some recording only when there is an authentic reason like sharing ideas and processes with other students, teachers and family. Why not develop a science programme that constitutes a series of 20-minute wonder sessions three times a week, where children experience a wide range of engaging experiences that fuel their curiosity? These could be related to seasonal or current events, and the students’ interests. They could be based around a particular natural phenomenon. In the process children will ask many questions that could be used to initiate authentic scientific inquiry as well providing a context for authentic literacy activity. A very simple and immediate action that all teachers could take would be to re-introduce the traditional ‘nature’ or science table to their classroom. This could become a science learning centre that provides an explicit science focus within the classroom throughout the year. Teachers could encourage children to bring their treasures and nature finds for sharing, talking about and exploring if appropriate. The nature table can be a source of ever-changing, independent activities. Computers, digital microscopes and other appropriate IT equipment can be set up to take advantage of children’s questions and their immediate desire for explanations. At the very least have magnifying glasses available for children to use as they explore aspects of natural phenomena. As a whole school, why not have a whole-term emphasis on ‘doing science’ culminating with a science expo?

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implementing the new curriculum Implementing the new curriculum poses many challenges for HODs, and in this article Graham Foster, Director of Science, Epsom Girls’ Grammar School, writes about his experiences. This article outlines the journey I have undertaken to try and grasp the ‘true’ intention of the revised NZ Curriculum (NZC), and to prepare resources that re-align teaching, learning and assessment in Science to the revised curriculum. It has been written to support other HODs (Heads of Departments) by providing a possible pathway towards implementing the new curriculum. The revised NZ curriculum identifies national priorities and considers curricular elements such as content, pedagogy and key competencies. There is also the need to consider the issues of: more explicit instructional strategies; use of inquiry and investigation; integration of the principles; values, key competencies. Finally, there is the issue of assessment/evaluation. The TKI website is a very good starting point for both HODs and staff who must be encouraged to engage with the spirit of the curriculum that goes beyond ‘tweaking and auditing’ current programme statements. Staff must also be supported to develop a cross-curriculum culture of sharing and the collaborative building of a coherent programme of learning. For me, this has been a challenge, and I have enjoyed being a part of our school’s strategic management team as we have explored this and other issues.

Looking at the new curriculum

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The 2008 new NZC aims to support today’s students to learn in a way that will prepare them for the world of tomorrow such that it: • includes a set of common values • places more emphasis on themes relevant to today’s society • contains five key competencies for students • raises the profile and status of learning a second language • raises the profile and status of statistics within mathematics • makes the Treaty of Waitangi explicit in the overview, purpose, principles and values • recognises the need for schools to work closely with communities to design relevant learning programmes. The curriculum also provides greater clarity for teachers, students and trustees by providing clear and simple statements about priorities, expectations and outcomes for each learning area. It also details the type of teaching that should bring out the best in students. And it gives back to teachers greater freedom to choose what students learn (you may recall the ‘hearts and hands’ of the ‘80s). Impacting on the new curriculum is the Ministry of Education ‘Personalised Learning’ document that was published in 2006. It emphasized that teachers should shift from developing better learning experiences to enabling students to become better learners. Therefore, we need to design learning experiences that enable individual student development – changing the focus to providing programmes of learning that better meet

the needs of individual students to develop critical competencies. How do we develop better learning experiences? I have found Graham Nuthall’s book entitled The Hidden Lives of Learners (published by NZCER) helpful. Graham’s research discusses the three worlds that learners bring to our classroom: the personal; social; and teacher intended world. I strongly recommend this as a must read.

What is my school’s approach?

As a whole school staff we explored the possible needs of students in 2016 and what society might look like in the future using Secondary Futures themes of ‘Inspiring Teachers’ and ‘Students First’ as starting points for the discussion, allowing us to gain a better understanding of the ever-changing world of our students. From this, our staff explored key competencies by using the resource entitled Iceberg (by Rosemary Hipkins, NZCER) as the starter exercise in our learning area groups, and Kick Starts (NZCER). Then at a regional HOD professional development day we looked at Kick Starts 2 exercise: The Water Cycle. This enabled us to see how to move to a more student-centred approach. Meanwhile in our school we continued to discuss the Key Competencies, providing a wonderful opportunity for the various learning areas to share what they are currently doing. This helped us to better understand our own situation, what we needed to continue and identify the opportunities available to us. For example, opportunities were explored at a specific cross-curriculum meeting between the Science-Mathematics departments to ensure coherent and supportive teaching in both our programmes. We also developed a small one-off project between the GaTE-Philosophy and Science programmes for the Rutherford essay. We explored effective pedagogies as outlined in the curriculum document by posing the question: How do we in our learning area…establish positive relationships with our students; provide opportunities for students to adapt their learning for their own purposes; encourage students to take their learning in our subject and apply it elsewhere; show we value the knowledge of others? etc. We then looked at the school-wide issue of “why do we need a Managed Learning Environment?” This allowed us to look at the amazing potential of ICT: student management systems including MUSAC programs or their equivalents; learning management systems such as Google, KnowledgeNet and Ultranet; eaSTTle, KAREN (Kiwi Advanced Research and Electronic Network) and TKI, all of which add to the collaborative and individual student learning. We realised that teaching and learning will not always be teacher centred, or based around specialised subjects, but instead students might be working with different combinations of teachers, at different times, all depending on when they might need to utilise their expert knowledge. So in the 21st Century the curriculum needs to give more equal emphasis to the key competencies: Participating and Contributing; Managing self; Relating to others; Thinking; and Using language, symbols and texts.


Some guidance from the experts

Transforming our programme An excellent video entitled ‘Inquiry learning and key competencies. Perfect match or problematic partners?’ presented by Rosemary Hipkins, NZCER, (and can be viewed on the TKI website) showed us how key competencies could transform the learning process by making pedagogy much more explicit. It used the context of ‘How safe are your sunglasses?’ and we have subsequently developed this more fully and is presently being trialled at EGGS. Yet before we could put this all in

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As part of our whole-school professional development, Mark Treadwell explained how the brain‘s development impacts on learning. He reminded us that sometimes we need to be “passionate and non-rational” and to respond intuitively. He explained that as the frontal lobe develops we gain astrocytes that map many of our automatic responses into our permanent memory. These astrocytes enable us to form new conceptual frameworks and sequences, and because they are covered with hormone sensors this enables us to sense emotions. Mark points out that to wake up neurons we must dump adrenalin into the synapses – all because strong memories are related to emotions and passionate experiences. For me, this follows that passionate teachers can elicit hormonal responses causing patterns in our memory. In our adult brain it chooses to remember how we do things so that we do not need to do them so consciously. But students’ brains are less efficient at this as they are still transferring new ideas and processes from their temporary to their permanent memory. This has brought more relevance to some of our previous professional development experiences about ‘thinking skills’ and engagement of GaTE students at EGGS. We are now more aware of the real needs to include really engaging activities and include specific memory enhancing pedagogies that integrate the Key Competencies and Values. Mark also introduced us to a book entitled ‘Five Minds for the Future’ by Howard Gardner. The five minds are: disciplined mind; synthesizing; creative; respectful mind; and ethical mind. These reflect the changes in the curriculum where the Key Competencies transform the teaching and learning and bind the whole learning process together. As I have written resources for the new curriculum, it has been very enlightening to see the change in perspectives. For example, when writing a full resource for the crosscurriculum study How Safe are Your Sunglasses? the change in emphasis from content about light, colour and the spectrum moved to a more life-relevant and socialscience perspective (balancing personal choice and regulations). This did not diminish the importance of the science content, but it did bring much more engagement and relevance to students at every stage because the teaching and learning strategies became much more specific and naturally integrated the Key Competencies and Values. I resolved the issues of assessment by giving guided responsibility to the student for self-assessment, using specific strategies, and after I took responsibility for setting the objectives and the expected criteria at the appropriate level. We were privileged to host Dr Rosemary Hipkins in September 2008, when a number of teachers from several schools met with her. Rosemary writes that: “Both the ‘93 curriculum and the current one, when combined with NCEA, do afford some curriculum freedom – if schools choose to take this up. The point is well made by Rachel Bolstad in her Curriculum Matters article (Edition 3) or in the book she co-wrote with Jane Gilbert that was published earlier this year.”

a teaching and learning focus it was necessary to ensure that our Learning Area statement and the classroom curriculum were aligned with the school-wide ‘Vision’ statement. Currently we are looking at the potential of using a wireless network with pods of mini-laptops; although there are discussions about: should we immerse students in these electromagnet fields when not a personal choice, time to set up and close down the computers, plus maintenance and funding issues. We are also exploring and discussing the huge potential for student engagement in collaborative research projects whereby students are encouraged to think, participate and contribute, and to use language, symbols and texts to evaluate the validity of information and gather ideas to form concepts. We have just started to look at how we might present our units. We are aware that some schools have produced unit formats which explicitly detail the key competencies, pedagogies, values, future focus themes, etc and we are considering them also. To reduce the content we might limit the number of specific learning outcomes and/or consider providing perhaps ten units, from which the teacher chooses six or seven for the year depending on the needs of the students in their class. The question of assessing the key competencies is still to be considered fully. While there have been discussions about self-assessments, particularly using Moodle, it was good to read ideas from Rosemary Hipkins’ paper Assessing Key Competencies: Why would we? How could we? (Ref: http://nzcurriculum.tki.org.nz/references) and from an ACER paper, written by Professor John Hattie, What is the nature of evidence that makes a difference to learning? In the former we are reminded that assessing key competencies might involve a ‘complex performance’ and that we need to explore ways of including students in making judgements about their learning…without relinquishing professional responsibility for gathering assessment feedback to inform next learning steps or to report for accountability purposes. Perhaps Moodle will be one way to do this. John Hattie explains that “the location of evidence that makes a difference to teaching and learning must be located at the teacher level.” So we are now more aware that it will be the formative process that is more important than the summative. Michael Fullan’s comments in the 24 November 2008 Education Gazette: “there is a need to focus on implementation and spread of effective practices.” and “capacity-building first, accountability follows …,” seem to provide a good reminder that, as we move along the pathway towards implementing the revised New Zealand Curriculum in Science we shall need to provide strong support for our science staff, to start small and try some ideas to determine what might provide the best way to implement it. Throughout our journey, I have had to balance the readiness and availability for change with a busy schedule of teaching and assessment, plus an understanding of the needs of my staff to move on with the considerable changes suggested by the revised NZ Curriculum and the potential huge benefits for students and science. My staff has shown considerable willingness to understand the changes and to consider them positively. We are now at an important time when we are ready to consider how we can implement the changes. I hope other HODs are able to experience staff willingness and positivity, too. For further information contact: grahamfoster59@gmail.com

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is Matauranga Maori science? People who raise this question generally suppose either that they have significant reasons to answer ‘emphatically yes’ or that they have significant reasons to answer ‘emphatically no’. But Philip Catton, co-ordinator for History and Philosophy of Science, University of Canterbury, explains why we should consider the question itself a harm, both to the understanding of intellectual accomplishments by traditional Maori, and to the understanding of science: The question whether Matauranga Maori is science inadequately respects the form of either kind of intellectual attainment. ‘Matauranga Maori’ is a name for various very rich knowledge structures that were adapted to Aotearoa/ New Zealand and to the needs for survival and flourishing of its indigenous people and that significantly developed over time partly as people learned more and partly as their conditions changed. Parts of Matauranga Maori were within the ambient public knowledge of all Maori, maintained by public uses of the oral memory arts that directly conditioned the lives of all in any iwi or hapu. Matauranga Maori made interesting all the minds that it helped thus to fill with knowledge, and brought about far greater like-mindedness among people than ever we experience today. Its character changed over time partly as conditions changed, and its usefulness for survival and flourishing was palpable. Any of us today would be dysfunctional or lost within the material conditions of life within which Matauranga Maori helped its possessors to flourish. Across its further reaches, Matauranga Maori was highly cultivated, roundly specialist knowledge, developed in the minds and by the experience of specialist inquirers, who had had a kind of exacting apprenticeship in this specialist form of life, and who were looked to by their fellows to perform a specialist, knowledge-keeping and knowledge-enhancing role. The ways in which the singular expertise of such knowledge specialists was not only cultivated but also made to condition societal decision making is a further kind of social accomplishment, key to the survival and flourishing of traditional Maori people.

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All aspects of Matauranga Maori represent high intellectual attainment by a people whose culture was oral. That the traditional culture was oral gave Matauranga Maori a form of which most present-day people have but the poorest grasp. Present-day people typically also possess but a poor grasp of science, yet examples of the character of science are, by comparison, significantly more current and accessible. Inevitably present-day people are interested in whether Matauranga Maori is science, and furthermore, in whether the knowledge-specialist kaumatua in traditional Maori society were scientists. Yet comparison with science

harms far more than it helps the task of understanding Matauranga Maori. In particular, the purposes and attainments of the relevant knowledge specialists in traditional Maori society are seriously misconstrued when compared to those of present-day scientists. By contending all this, I am putting myself in an isolated, uncomfortable position, different from those, and there are many, who have wanted to claim that Matauranga Maori isn’t science, because they are answering that question, and they are answering it in a way that represents a challenge to the enormity of the accomplishment intellectually that Matauranga Maori is. I am also however, opposing those who say of Matauranga Maori that yes it is science, and although I am in agreement with them that we must recognise in Mataugranga Maori a wealth of knowledge, and recognise the enormity of the intellectual accomplishment that it represents, still I want to say that calling Matauranga Maori ‘science’ doesn’t do justice to the kind of intellectual accomplishment that it is. To talk about Matauranga Maori is to talk about an accomplishment within oral culture − or at least, an accomplishment within a culture that is profoundly oral, though it is at the same time making use of some exosomatic means (for example carving, string games) of making facts memorable. Oral cultures make use of people’s minds to make room for all the enormous number and varied forms of facts that need to be recalled in order to make life possible, and good. Any people needs to have assembled vast knowledge in order to survive and flourish, and some peoples find means mostly in people’s heads for holding all of that information. They establish within the performance of talk and spoken ritual means to propagate that information down the generations, so that the information remains available generation after generation and the society can continue to survive and flourish.

Maori used aids to memory A profound difference, therefore, between Maori in their traditional setting and people who may be acting in science laboratories or, say, in science departments in universities today, is that the means for propagation of all that is known in the one case is largely oral, and in the other case is largely through what people tap through their computer keyboards, ultimately for storage in computer memory banks or printed journals or books, utilising a writing down of language. Maori had made very extensive use of exosomatic aids to memory. But these aids are to be understood as powerful extensions to the oral arts of memory. People already adept in oral arts of memory can find significances in carving or string games that further extend the already vast reach of their oral mnemonic structures. Maori exosomatic symbolic forms − such as carving and string games − are not an interruption of oral arts of memory, but rather extend them.


Using mnemonic arts Let me illustrate in a mundane way what it is to use the mnemonic arts. When you are being introduced to many people at once, and you are challenged to remember all their names, the way forward is to associate a playful mnemonic with every name. It is crucial that you be spontaneous, imaginative, and, over against the demands of literal mindedness, irreverent. Roger Sandford is introduced to you, and you seize playfully on an image of him saying “roger, roger” into his cellphone as he drives to the beach in a Ford. This image is not literally true. But it is enormously useful for memory. You now have an image to hold onto that combines all the elements of his name: roger, sand, Ford. With this image comes a powerful ability to retain this item of information and recall it at will. I suspect that you will remember at the end of reading this article the name of the man mentioned in this example. Perhaps you are especially imaginative, and produced an image of Roger that is sharp and lasting. It would in that case not surprise me if you were still able a year from now to say what the man’s name is. If a people depends on their minds for the retention of all the information that confers upon them the powers of survival and flourishing, then they have to make use of just such devices thickly and constantly. They have to come together to enhance the powers of such play of the mind to make memorable a vast, vast store of information. When they do so, what they are doing is of a different character from simply organising information into some final, theoretical form. It is misunderstood if it is compared with the effort to organise information in theoretical science. When one is told of this ‘South Island’ (Te Wai Pounamu) of ours that it represents what happened when some long-ago figures − deities, ancestors, it is a bit ambiguous − in their waka leaned forward and, somewhat forward of mid-centre, froze, you get an idea of the topography of this island. It makes memorable how the mountains are, how they are in the island, a bit about their structure (the strata line up that way). You have an image of what you will see. You make memorable many facts about the landscape that it will be useful for you to know. You would completely misunderstand the significance of that story by considering it a theory, an attempt to explain the island, an attempt to state its cause. It is no more to be understood just that way than is my image to you of Roger’s saying “roger, roger” into

his cellphone while driving to the beach in a Ford an explanation of why the man’s name is Roger Sandford. It is instead a device for making things memorable, and the people who would put up the waka story in order to make memorable facts upon which their lives will depend won’t be mistaken about that. They know that they are creating memory arts. Their lives depend upon their having the memory arts constantly at their disposal. Likewise, if one considers an early ancestor or semi-deity to have used an enormous adze to make parallel strokes in the southwest corner of Te Wai Pounamu (the South Island), one makes extremely memorable the topography of that place, one sees the sounds, one feels familiarity with their character. One also provides a story which could be the beginning point for other stories which would make memorable still further features of that landscape, pointing to significant further facts about that landscape, such as resources that it contains (pounamu, or greenstone, among other things), dangers that lie there, the way it varies in its conditions season by season, how the resources can be collected and used, and so on. If you are making it possible to live in as challenging an environment as Aotearoa/New Zealand, then you are desperate for ways to make a vast amount of information able to be propagated down the generations. And if minds alone are what you’re going to use to do that, then you will work to make minds rich and interesting, filled with stories that flesh out these mnemonic arts.

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By contrast, within the present-day cultural circumstance of which science is a part, there clearly has been an interruption of oral memory arts. These arts are thoroughly displaced by the information storage and retrieval systems that involve the written word. We don’t have our memories any more. Our minds are blank in ways that the minds of all peoples up to the last two or at most two and a half millennia were not. Most present-day people know nothing much about what it would be to be a recipient of powerful mnemonic means to hold in one’s head a vast proportion of what a people can know about both their environment and themselves in order to make living together and surviving and flourishing within a landscape possible. Those who do know, know in not as full a way as that of people whose entire intellectual circumstance was of an oral culture. The echoes − important, and important to preserve − that there still are, of the powerful mnemonic arts of earlier Maori, are slight, so that people who are deep into what does remain of those arts today are nonetheless seeing less than what people only a few generations ago would have been equipped by those arts to see.

Passing on knowledge I really want to emphasise that in my view inheritors of an oral culture have minds that are interesting and full to an extent that we scarcely, if ever, see around us today. We have lost these arts. Consider you. You are inheritor to a tiny, miniscule fraction of the culture by which we are surrounded. Consider me. I am inheritor to a tiny, miniscule fraction of that culture. Moreover, the part that I have inherited is different from the part that you have inherited in enormous degree. We are alienated from each another. We don’t know that much about each another’s minds. Very little has passed into us that would make us similar. And this is a rather uncomfortable, alienated, situation to be in. Our bonds with our fellows are not that strong. Consider by contrast members of a society whose whole culture is oral. Almost the whole culture will pass into their minds. That’s an exaggeration, because of course there will be some skills that are specially concentrated in a few; but enough will pass into every person’s mind to give everyone an intimate knowledge of what anyone else in the society can do. A vast amount of total public knowledge will become the knowledge of every person. You can consider the situation of a people whose culture is oral to be such that unless each new person born into that society is treated as a vital resource, to aid with memory, to help propagate the total culture along, then there is a threat to the entire society. Everyone’s mind must over time become a vehicle for this public, societal knowledge, that makes survival and flourishing possible. In an oral culture everyone, day by day, hour by hour, activity by activity, is swept up into consideration, together, of the mnemonic arts. The myths that are these mnemonic arts will be constantly re-told. They will shape decisions about what to do, where to go, how to get this, what to do with that, how to get along, when to stop and when to move on, what to aim for next. Practical life will be informed by a vast wisdom about what works, that has been carried to the present generation by the means of these mnemonic structures. Tradition connects people, not only who are contemporaries of one another but also ever so strongly across generations.

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The Enlightenment The activity of theoretical science is by contrast appreciably conditioned by so-called Enlightenment values; scientists are literally minded people, seeking through discussion to proportion credence simply to the unforced force of the better argument. The question concerning some idea that is discussed of whose that idea is, where it has gained its traditional authority, what would the ancestors (if they pondered it) think, is treated automatically as ill-directed, officially unimportant, pathological. All that is allowed to count are present reasons − reasons in rational support of the idea, or reasons in rational criticism of the idea. This makes science capable of some remarkable things − things that illustrate the lengths to which high literal mindedness can carry one. What is the biochemistry of the muscular contractions in the mandibles of some particular species of beetle? A scientist can spend an appreciable portion of a career investigating the answer to some such question as that. It is weird, but beautiful. Occasionally it produces what is of undoubted practical worth. The beginnings of an understanding of a potential cure for some muscle-degenerating disease might lie in just such amazing arcane science. Being literal minded in the extreme, and far separated from the mytho-poetic mindedness of peoples practising memory arts, can be wonderful, and there are many

philosophers who defend this cultural orientation with abiding passion. The philosopher Karl Popper was one such, writing, in Christchurch, in the late 1940s, his great book The Open Society and Its Enemies, which is a clarion defence of Enlightenment values, and a passionate diatribe against ‘tribalism’. It seems to me clear that when fellow philosophers such as Popper passionately defend their Enlightenment values they sometimes go too far, say what is false about the need for these values, and even imply an insult against Maori. Indeed, I maintain that that is the case in Popper’s world-famous book above-mentioned. The passionate defence of Enlightenment values can go too far when it fails to acknowledge both the potential functionality within other cultures of a different ideal for discussion, and indeed the impossibility of the functioning of Enlightenment kind of ideal except within a very unusual, recent and not unproblematic modern cultural form. I shall elaborate in due course both Popper’s point of view and some objections that I have to it. First, next issue of the NZST (121), I shall consider ‘Matauranga Maori, Science, and Truth’. Then in the issue after that (issue 122) I explore why ‘Matauranga Maori Refutes Popper’. For further information contact: philip.catton@canterbury.ac.nz

ask-a-scientist createdbyDr.JohnCampbell Do large public fireworks displays do any damage to the atmosphere or the ozone layer? Dianne Bryant, Dunedin. Anthony Lealand, of Firework Professionals Ltd www. firework.co.nz who manufacture pyrotechnics and produce large public displays, special effects for theatre, films and indoor pyrotechnics throughout New Zealand and the South Pacific responded: Our largest star shell (400mm) bursts at an altitude of 700 metres and the burst radius may extend the highest particle to 1000 metres, which is very low compared to volcanoes and aeroplanes. Large public fireworks shows involve many types of fireworks but when averaged are equivalent to using about 2000 x 100 mm star shells. Each of these has a propellant charge of 50 grams of black powder and a similar amount for the explosive charge. This gives a total of 200kg of black powder per event which is 20 per cent carbon. This releases 73.4kg of carbon dioxide into the atmosphere. Other oxidisers and fuels are used producing the colours and finally solid by-products which are seen as smoke − for example, MgO and Al2O3 (white), BaO (green), SrO (red), and CuO (greens and blues). The main gas produced is carbon dioxide, followed by approximately half the weight of sulphur dioxide. By comparison a typical jet aircraft (777) flies at 10km altitude burning 6000kg of jet fuel per hour which when burnt produces 18,500kg of carbon dioxide. Concorde burnt even more fuel: 22,500kg per hour. If the 50,000 people going to the fireworks show travel by cars, each holding four people, and travelled an average of 20 kilometres there and back, we would have 12,500 cars, travelling a total of 250,000 kilometres. A reasonably modern European subcompact car will emit approximately 140 grams of carbon dioxide per km. Therefore 50,000 people attending the show produce 35,000kg of carbon dioxide. The fireworks display is thus a very minor part of this total, less than 0.3 per cent.

How do they make the special effects on TV like when a shop blows up just as someone is leaving it? Campbell McKay, Ridgway School. Anthony Lealand, a pyrotechnic scientist who formed The Fireworks Display Company of Christchurch and who regularly devises special effects for orchestral productions, celebrity openings, advertisements, movies and TV programmes, responded: Real explosions are actually quite boring looking things. There is a fast flash, objects fly about so fast you wouldn’t see them on video and generally there is only a small puff of black smoke. This is because an explosion is the result of a very fast chemical reaction and most explosives are carbon rich. In other words there is not enough oxygen to burn the carbon in them. However, this is too boring for television and film. For these explosions we use low explosives, such as gunpowder and nitro-cellulose, which are very slow and which therefore do not generate a supersonic bang. These are triggered by electrical ignition so the sequence of explosions is under the careful control of the explosive expert and/or his/her computer. For example, as an actor runs from a building a whole sequence of explosions can be initiated. For effect, these explosives are placed inside bags or drums of fuel which ignite to give the glowing fireball effect. Frequently, other pyrotechnics effects are added, such as mines or mortars or cannons that will blow out white stars or titanium powder to form white sparks. The procedure is messy, dangerous and frightening to rig because the liquid fuels could be ignited by chance sources of ignition. This can go horribly wrong unless one has had considerable experience. The whole effect is a comic book explosion totally unlike a real explosion but fully satisfying the visual demands of television and film. For further information: questions@ask-a-scientist.net


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written by John Brooks, Professor of Food Microbiology, AUT Try this quick quiz: How many meals did you have in the last two days where microorganisms were involved in a good way? The chances are you can think of one or two items – yoghurt and cheeses, perhaps. Did you include bread, salami, pickles, soy sauce, beer, wine, tea, coffee or spirits? Microorganisms (bacteria, yeasts and fungi) are involved in the production of all of these foods and beverages. Food manufacturers, guided by microbiologists, expend considerable effort to control the activities of these living organisms to produce high quality, nutritious foods with acceptable shelf life. The other aspect of the job is to ensure that food products are safe to eat. There are literally thousands of different microorganisms, but only a few cause illnesses in humans. Of these, only a very small number are transmitted in food. Understanding the interactions of microorganisms, foods and consumers is an essential part of the food microbiologist’s job. Foods are characterized by a set of intrinsic parameters, the most important being pH, water activity and composition. The extrinsic parameters, such as storage temperature and oxygen availability, combine with the intrinsic parameters to determine whether microorganisms will grow in the food. We can take advantage of this understanding to make subtle changes to raw foods to make them safer. For example, if we have a particular food with pH around 6.5 and water activity of 0.96 we might expect that many different types of bacteria will grow in it. To extend its shelf life or ensure the safety of the consumer, we might lower the pH by adding an acidulant. By itself, this is not likely to stop microbial growth completely, so we resort to the hurdle approach. (Think about sending your pupils out onto the athletics track to run the 100m hurdles. Most students will jump the first hurdle successfully, but some may fall at subsequent ones). We set up several different hurdles targeting different aspects of the microbial cells. By adding a humectant – a chemical that reduces water activity – we combine two hurdles to growth. Many microorganisms require oxygen for metabolism, so by vacuum packaging or modifying the atmosphere in the package, we add a third hurdle. If that still doesn’t prevent spoilage or growth of pathogens, we can specify that the food should be stored under refrigeration until its ‘use-by’ date. Another approach is to remove the pathogens – milk and other products are pasteurized by heating, which kills all the vegetative pathogens, while canned foods are sterilized by the heat process. One of the most fascinating aspects of microbiology has evolved over the past twenty-five years. Since the times of Pasteur and Koch, microbiologists have worked with pure cultures of microorganisms, often growing them in various broths. We now know that the normal mode of growth for many microorganisms is at a solidliquid interface. These aggregations are called ‘biofilms.’ Everywhere we look, we find biofilms growing – in our mouths, in our intestines, in streams, on food processing equipment and in our factories – forming complex communities in which the individual cells communicate

via chemical signals. Biofilms are quite different from free-floating cells and are often much more resistant to cleaning and sanitizing. It is therefore essential that we study biofilms to ensure that we can control them. The School of Applied Sciences at Auckland University of Technology (AUT) is collaborating with colleagues at Massey University to study aspects of biofilm growth. Over the last few years, the group has investigated the growth of thermophilic bacteria found in milk processing equipment. These microorganisms have the potential to cause major economic loss, as their presence in milk powder results in downgrading of quality. The cells attach firmly to plant surfaces, such as stainless steel and rubber, producing a polysaccharide glue that makes them hard to remove and protects them from sanitizers. (Refer Figure 1)

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Figure 1: Scanning electron micrograph of Bacillus biofilm growing on stainless steel, showing the polysaccharide slime that attaches the cells to the surface. Photograph courtesy of Doug Hopcroft.

Figure 2: Scanning electron micrograph of microcolonies of Enterobacter sakazakii developing on silicone feeding tube. Photograph courtesy of Dough Hopcroft and Baizura Md Zain.

Unfortunately, some pathogens also have the ability to form biofilms and may be the cause of serious illness in neonates being fed through synthetic rubber tubes. Since these tubes may remain in place for days or weeks, buildup of a biofilm may allow the infant to be continuously inoculated with the pathogens. (Refer Figure 2) Since the biofilms cannot be removed, we need to develop materials that do not become colonized and to this end, Masters and PhD research students in the group are studying the factors that affect the colonization process.

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by Melva Jones Science books with an NZ focus As a librarian who provides resources for school students, I find it frustrating, at times, trying to fill requests on topics for which we have little material with a New Zealand flavour. This is a reflection, of course, of the size of our country and the relatively small market there is for books on NZ topics. However, during the last few months we have seen some great NZ books added to our shelves. All About New Zealand Birds by Dave Gunson, published by New Holland (2008). A great addition to our wildlife collection for young readers. Each page has a large clear full colour drawing accompanied by a few paragraphs and a text box, which gives the weight, length, lifespan, diet and distribution of the bird. The book has a brief chapter on birds of the past and then is divided into habitats. Atoms, Dinosaurs & DNA: 68 Great New Zealand Scientists by Veronika Meduna & Rebecca Priestley, published by Random House NZ (2008). A beautifully illustrated book which tells the story of New Zealand scientists who’ve made a significant contribution to the way we understand our world. The profiles are presented in chronological order and provide an exciting timeline of the history of NZ science.

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The volcano book: erupting near you by Dr Gill Jolly, published by Black Dog Books (2008). Written by an NZ scientist, this is an ideal book for primary level students who are being introduced to volcanoes as it brings the subject right to

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their doorstep. Beginning with a brief explanation of volcanoes and the ring of fire, it then looks at our volcanic regions including: Taupo, Ruapehu and Auckland, plus Mount Vesuvius, Mount Erebus and Mount St Helens. For more book reviews of titles held in the National Library’s collections, visit the Create Readers blog at: http://createreaders.natlib.govt.nz/ Rare Wildlife of New Zealand by Rod Morris & Alison Balance, published by Random House N.Z. (2008). Full of interesting descriptions, observations and facts about a wide cross section of endangered New Zealand flora and fauna, from forests and wetlands, high country and sea and shore, featuring lizards and snails, trees and flowers. This great little title is a companion title to Beautiful Birds of New Zealand by the same authors. The Awa Book of New Zealand Science edited by Rebecca Priestley, published by Awa Press, Wellington (2008). This book is written for senior students and adults. It is a collection of articles for both the scientific and nonscientific reader. Topics include: The 1855 Wairarapa earthquake, The rediscovery of the Takahe, and the establishment of a Carbon-14 Laboratory.

Not just about books From the start of 2009, National Library School Services will give school users the option of having web links sent directly to their email. Our staff aim to respond to digitalonly requests in 24 hours. Standard requests for book collections may also include web links and these can be emailed to you on the day the books are processed for mailing. Information and new request forms will be available in your schools from Term 1 2009, or online at: http://www. natlib.govt.nz/cis-online-request To ensure your books arrive in time for your teaching, please give us two weeks notice.

males less choosy than females Research from The University of Auckland, funded through a Marsden grant, studied the social behaviours of zebra finches. Male zebra finches, when given a choice between same species or other related finch species, did not show social discrimination. In contrast, female zebra finches consistently chose to spend more time next to male zebra finches over males of other species. However, behavioural displays of song and calling confirmed that males are able to tell females of their own and foreign species apart. The research, undertaken by PhD student Dana Campbell, BSc (Hons) student Rachael Shaw, and Associate Professor Mark Hauber of the School of Biological Sciences, is

published in the latest issues of the journals Ethology and Behavioural Processes. “By studying the mate choice of zebra finches, which form lifelong monogamous pairs, we can see that male birds are far less particular about the species of their mate than females,” says Ms Campbell. “These results confirm expectations of (the) Darwinian Theory and may have an impact on zebra finches in the wild, where they often live and breed in mixed species flocks in their natural habitat in Australia. It may also have implications for aviary practices, as the genetic pool may become mixed with inter-species breeding.” For further information contact: m.hauber@auckland.ac.nz


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Going underground is an exciting online resource that encourages soils to be used as a context in science classrooms, as Angela Schipper, Hillcrest Normal School and Louis Schipper, University of Waikato explain. The health of New Zealand’s waterways has been a hot topic for many years, but what about the health of the soil beneath our feet? Going Underground – Visual Soil Assessment, sponsored by the Royal Society (RSNZ), enables primary and intermediate school students to learn more about the soil in their immediate environments. Going Underground aims to get students thinking about the existence and importance of soil. While students are already aware of the signs that indicate humans are healthy, through hands-on activities they learn about the indicators for healthy soil and how land use within their school grounds may affect soil health.

Visual soil assessment (VSA) Going Underground uses a visual soil assessment (VSA) as a quick and simple way to measure soil health. VSA was originally designed by scientists at Landcare Research and Horizons Manawatu as an assessment tool for farmers. Our modified version of VSA uses visual scoring of three soil properties – structure; porosity; and earthworm numbers – to assess the soil from sites around the school. Students dig out a 20cm cube of soil, drop it three times and sort the aggregates (soil particles) by size. Students look at the soil structure to see if the soil breaks up easily when dropped or if it is full of clods. They examine the pores within the soil – cracks or holes that allow for air and water movement. Students finish

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by counting the earthworms in the soil. At each stage, students compare their findings to indicator photos provided and assign visual scores of poor, moderate, or good for each soil property. If time allows, it is ideal to perform a VSA on different sites around the school to see how use of the land affects the soil. Sites may include relatively undisturbed areas such as fence lines or ‘out of bounds’ areas, high foot traffic areas, areas disturbed by recent construction, etc.

Gingernuts versus Girl Guide biscuits Conducting a VSA is only one aspect of Going Underground. Chances are in many classrooms soil is only discussed when it arrives on the bottom of dirty shoes. To aid student understanding of why properties like structure and porosity are important to healthy soil, a number of introductory activities have been included. All activities require minimal time and resources. For example, soil structure and friability are related to the crumbly nature of biscuits. Students use household sponges to explore soil porosity (how air and water occupy spaces between soil particles). There are also suggestions for follow-up activities. These range from the way green spaces are managed at school to debating land use issues such as ‘to profit or to pug’?

Secondary school use Although Going Underground is aimed at younger students, the VSA portion is appropriate for senior students. In addition, the Royal Society will provide a free copy of New Zealand Soils on CD to those who request it (see below for details). The CD provides a comprehensive, visual introduction to soil science and the range of soils around New Zealand.

Using the planners

Photo left: Room 15 students at Hillcrest Primary School dropping the soil cube to break it into aggregates. Photo right: Figure 2: Room 15 students at Hillcrest Primary School undertaking an earthworm count.

Going Underground is found at: www.emap. rsnz.org/resources.php. Scroll down to the Soil section where curriculum planners are provided for Level 2 and Level 4 in the NZ Curriculum. The planning documents can also be adapted and modified to include specific learning outcomes, plus select or delete links to numerous curriculum strands, key competencies, values, environmental education and Enviroschools aims. References are made to current Ministry resources and to the GLOBE Programme for those schools wishing to explore soils and Earth science systems further. Note: New Zealand Soils on CD by Peter Singleton Environment Waikato, is available free of charge from the Royal Society. Contact Rebecca Goffin at: rebecca.goffin@rsnz.org or send a $4 self-addressed envelope to: EMAP, PO Box 598, Wellington 6011.

Photographs courtesy of Hillcrest Primary School.

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Ethical guidelines for secondary school students using animals and animal parts in practical classes Written by the Australian and New Zealand Council for the Care of Animals in Research and Teaching (ANZCCART). Introduction The use of animals or animal parts in practical classes is a privilege that brings with it the responsibility to avoid cruelty to animals. Students should make a commitment to the welfare of these animals and respect them for the contribution they make learning. Outlined below are five issues to think about. These will help you meet your responsibilities.

Why are animals or animal parts used in practical classes? Animals should only be used to enhance learning outcomes. Animals may be harmed to achieve these outcomes, and thought should be given to whether the learning outcomes can be achieved without the use of animals or animal parts. Students and staff should think about the Three Rs (Replacement, Reduction, and Refinement) when using animals in schools.

What are the requirements for animal welfare and animal handling? The welfare of the animals you use is your responsibility and not just your teacher’s responsibility. If you have to handle animals during a practical class, it is important to follow the instructions you are given about the correct handling techniques for the species you are working with.

What are the laws covering the use of animals and animal parts in practical classes?

ask-a-scientist

The use of animals in research, testing and teaching in New Zealand is covered by the Animal Welfare Act 1999. This Act has an underlying principle of a “duty of care.“ The act requires that approval be received from an Animal Ethics Committee (AEC) for using animals in schools. To get this approval the use of animals must be justified, the species and number used identified, the way the animals will be used described, and the learning

42

outcomes of the practical work balanced against any potential harm to the animals used. The skills of the staff involved and the supervision of the students are also evaluated. The questions raised by AECs should be asked by each student regarding the use of animals in their practical classes.

What do you think about using animals or animal parts in practical classes? You should discuss the use of animals with other students and staff. You should form your own opinion and, with appropriate justification, feel free to discuss your opinion in an open environment. You should feel free to make suggestions that might improve future practical classes.

Think about your responsibility to make sure that good use is made of the learning opportunity You should know the purpose of the lesson and the concepts that are being taught in the class. This involves being prepared by doing any reading of background material before coming to class, knowing about the procedures in a practical class, and being generally prepared to maximise the learning experience. You should also be prepared to use every opportunity to develop manual, observational, and recording skills during the practical class. To achieve its mission, ANZCCART promotes: • excellence in the care of animals supplied for or used in research, testing, and teaching • responsible scientific use of animals • the three Rs policy of Replacement, Reduction and Refinement as they apply to the use of animals for scientific purposes • informed discussion and debate within the community regarding these matters • strategic partnerships to contribute to the education and training of scientists, students and the broader community. For further information visit: http://www.royalsociety. org.nz/Site/About/Our_structure/advisory/anzccart/ default.aspx and: www.adelaide.edu.au/ANZCCART/

ask-a-scientist createdbyDr.JohnCampbell Why does infrared radiation get absorbed by carbon dioxide gas? Scientist John Campbell, a physicist at the University of Canterbury, responded: If we hit a tuning fork or pluck a guitar string or tap a thin-walled glass the object resonates at a frequency particular to it. Let us consider one process whereby light is absorbed by a molecule without chemically altering the molecule. Molecules with ionic bonds absorb infrared radiation. Carbon dioxide is a good example. It is a linear molecule whereby two oxygen atoms are bonded to a carbon atom between them and their electrons are shared so that the oxygen and carbon atoms are charged oppositely. Electromagnetic radiation applies an oscillating electric force to an electrically charged object.

When microwave radiation is shone onto a carbon dioxide molecule the carbon atom and the oxygen atoms oscillate with respect to each other. If we increase the frequency of the radiation to about thirty million, million times a second (in the infrared region of the electromagnetic spectrum) we strike a frequency at which the atoms resonate. At this frequency the molecule strongly absorbs energy from the infrared beam in order to keep the resonance going. This natural frequency of resonance of the carbon dioxide molecule forms the basis of the carbon dioxide laser which is the most efficient gas laser for turning electrical energy into infrared radiation. In New Zealand such lasers are used in industry to cut sheet steel and in women’s hospitals for internal surgery. For further information: questions@ask-a-scientist.net


NZ

science teacher

by Jacquie Bay Often, as teachers, we use the history of science to create some of the best and most memorable learning experiences and lessons. I could not imagine introducing concepts of the atom, plate tectonics, heredity or DNA structure without creating opportunities for students to at least learn from the history of how these concepts came to be understood. History of science can also be used to help students appreciate the impact of science on society. An experience that I have often used in different guises with Year 12 students has been to ask them to create the front page and editorial of a London newspaper in the week that The Origin of Species was published. Darwinâ&#x20AC;&#x2122;s anniversaries this year will provide further impetus to explore the history of the development of these ideas with our students, but how often as teachers do we glance back at the history of science education and consider the impact of this on the directions that we are talking? Biology, as a science, has made extraordinary progress over the past 150 years. Biology education has followed, and is a branch of education where the pace of knowledge development, the complexity of the knowledge and its impact on society makes for stimulating and challenging classrooms! Glancing through the history of NZ science education we find that although science was introduced to NZ schools in 1878, biology as a science was immature at the time, and as a result the botany and zoology that we can trace in early NZ educational history show a rather dry study of form. Despite this, we can see that educators at the turn of the century wanted science and biology education to be relevant to the students. In primary schools and lower forms of secondary school, agriculture hygiene and human physiology joined botany and zoology and we read of the desire of authorities to make education relevant to the lives of the students. Although introduced by name as a subject in 1934 at School Certificate level, biology as an integrated study of form, function and diversity of living organisms is not seen in the sixth form until the 1950s. This only occurred once the relevant biochemistry was developed, and concepts of cellular function, metabolism and heredity, central to all living organisms were clearly established. If the period up to the 1950s led us to a point where biology education was established as a study of form, function and diversity, based on the principles of evolution, the 1980s saw the emergence of the Science Technology and Society movement which established the need for biology education to allow students to explore the impact of biological advances on society. While initially this tended to revolve around conservation, incidence of human disease and biological control, by the early 1990s the influence of molecular biotechnologies were entering the curriculum, and for the first time we

biology

looking back as we move forward

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saw biology education keeping close pace with advances in biology. While concepts of heredity took almost 50 years to impact on biology education and Darwinian principles 100 years, advances in molecular biology that are underpinned by complex science are flying into the classroom often less than 10 years after their development. There is no doubt that life processes, ecology and evolution are the central concepts of biology education and that understanding of the nature of science is essential. The NZ curriculum is well founded. There is also no doubt that the biology and science that underpins issues such as global warming, modern health issues and GE is more complex than the biology underpinning the issues of hygiene, conservation, health and agriculture relevant during the last century. Current social and economic issues drive the need for a population that is able to follow scientific debate, and make decisions on whether to trust the views of scientists. While in the early 20th century we could see the desire to develop scientific literacy that empowered individuals to make decisions in their daily life based on an understanding of the underlying concepts, the 21st century needs students in addition to be able to judge the work of scientists and decide whether to trust the findings of science. While we continue to need a biology education that allows students to develop understanding of concepts such as the carbon cycle, digestion of food, heredity, the spread of disease (and we could spend many hours debating just what is essential!) what we also need is an education that encourages the development of a scientific literacy that promotes understanding of the process of science and the development of scientific evidence. We have a curriculum that encourages this. The process of aligning the standards to that curriculum is an important one, and will require science educators, scientists and the community to engage together in debate about what the essence of good biology and science education for the 21st century will mean. The Biology Educators Association of New Zealand has been very grateful for the way in which teachers throughout the country are participating in the process of alignment of the standards to the new curriculum. Change is continuous in education, including biology education which is constantly growing, and there are also other challenges. The process of evolution of the standards requires patience, foresight and persistence. Most importantly, in the same way as we need to develop students who have the capability to trust the work of scientists, we as teachers must actively engage with NZ society about the needs of students in our biology and science classrooms and gain the trust and understanding of our communities. For further information contact j.bay@auckland.ac.nz

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science postcards

by Dr Chris Astall andWarren Bruce, College of Education and Education Plus, University of Canterbury Free, innovative resource Primary Science has certainly been in the spotlight since the publication of the New Zealand’s National Education Monitoring Project (NEMP 2007) and The Trends in International Mathematics and Science Study (TIMSS 2007), and there has never been a better time to share the Science Postcard resource. The NEMP (2007) report identified that Year 4 students ‘sensed a lack of science activities at school, and particularly a lack of “really good things” such as experiments and research/projects.’ Science Postcards were developed with the support of the NZASE to offer children science experiences whilst supporting the nonspecialist primary teachers. Science Postcards are free, innovative resources designed to support your primary science teaching and downloadable from www.sciencepostcards.com, and provide children with ‘hands-on, minds-on’ learning experiences, coupled with the curriculum support for primary teachers. There is a real need to offer children valuable learning experiences based around clearly identified science concepts, whilst at the same time making the teaching of the Nature of Science explicit. Using children’s fiction texts provides a framework and context for the science activity, allowing the teacher to engage the children. The Science Postcard provides the motivating link between the book and the science activities which are chosen, and offer both the ‘wow’ and ‘awe’ factor of science.

Development of science postcards The idea of the postcards developed from the 2007 NZASE Primary Science Conference ‘Enhancing Science Understanding With Literacy Practices: Using and Creating Texts.’ A group of enthusiastic primary teachers wrote and trialled the initial Science Postcards. They proved to be so successful that the NZASE provided funding that allowed eight cards, support materials and the website to be developed. Since their inception, the editors have provided workshops for primary teachers based around the Science Postcards in Christchurch and Wellington and, in 2009, will provide workshops at each of the four venues for the 2009 NZASE Primary Science Conference ‘Active Learning: Science talk from the classroom to the dinner table.’

Using science postcards The resource consists of:

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Science Postcard that features a storybook and has a discussion starter message for the class/child Teacher notes detailing the science concept, nature of science, links to 2007 NZ Curriculum and supporting NZ Ministry assessment material and publications (e.g. Building Science Concept books, Making Better Sense series, TKI Digistore, Connected series, Journals, Assessment resource bank activities). They also offer clear teacher support in delivering the ‘Nature of Science’ strand through the section ‘Science in the Real World’. Pupil notes that clearly outline the science activity and includes questions to develop scientific thinking skills

Supporting website where teachers can download, for free, all the Science Postcards, pupil and teacher notes. It has links to ‘Science in the Real World’ and other websites we have found useful. Science Postcards are designed to be used in conjunction with a storybook. The action of capturing a child’s imagination through a beautifully told story, to providing opportunities for the child to explore some of the science within the story is an incredible motivator for both the children and the teacher. The science ideas or concepts that have been identified within the stories can be developed and used as starter for a science topic or unit of work. The Science Postcards can also be used as one-off activities with the focus on developing the children’s understanding of ‘what is science?’ through the Nature of Science strand of the curriculum. The activities were carefully chosen to provide opportunities for teachers to challenge the scientific ideas and beliefs of the children. We firmly believe that this constructivist approach to learning is very important, and that children should be allowed to share and develop their ideas and that these ideas should be challenged and built upon. The activities also support particular science skills (e.g. creating and using data tables or making observations) and they allow teachers and children to explore scientific ideas in everyday situations – a ‘Science in the Real World’ approach. At the moment there are eight cards in the series and the editors are currently writing the next set. A collaborative project between four NZ universities is exploring the effectiveness of the Science Postcards in developing teacher’s understanding of the Nature of Science. The website has over 600 members worldwide and is receiving 20,000 hits a month. So login, register for free and download this superb resource. Use it in your class and let us know how it went. If you have an idea for a storybook we could use, or an activity you would like us to develop, then share your ideas. Don’t forget, the editors of Science Postcards will be offering workshops at each of the four 2009 NZASE Primary Science Conference venues.


NZ

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physics

the changing resistance of graphite by Paul King Pencil Lead is a mixture of graphite and clay. The graphite will conduct electricity so a current can be passed through a pencil sharpened at both ends. The heat released by the current excites valence electrons into the conduction band resulting in a greater current. The heat has reduced the resistance! The greater current releases more heat which creates even more current and we have positive feedback. The growth of the current is limited only by your power supplies circuit breaker or the pencil lead becoming hot enough to radiate the heat as fast as the current delivers it (and so comes to a steady temperature).

Save for a finale connecting up a few centimetres of mechanical pencil refill, the thin stuff. This is hard to do because the croc clips tend to snap the thin lead but with care it can be done. The rod will glow with startling brightness as you discourse on the original incandescent electric lights. Which had their carbon filaments inside a glass bulb containing an inert gas. Your thin pencil lead (not in an inert atmosphere) will by now have oxidised to CO2 and snapped. Once eyes have recovered a pair of carbon fibres will be found hanging from the clips. This is easy, cheap, safe, spectacular, relevant, open ended. The perfect demo?

What to do Full length pencils come to thermal equilibrium at quite low temperatures so use an HB stub, about 6 cm long. Connect with crocodile clips – use uncovered old clips; they are going to get hot. Put the pencil on a sacrificial tray unless you want more scorch marks on your demo bench. If you are taking readings (probably current v time) consider using the giant old analogue ammeter from the store so the whole class can watch the steady increase in current until the volcanic pencil takes over their interest. 12 volts will allow an initial current of about 1.0 amp which will increase over a minute or two to a steady 2.5 amp. The pencil will be history, smoking violently, probably in flames, splitting down its glued seam (you know how pencils are constructed? You will now.) revealing a red hot glowing rod.

12 V Power Pack D.C. if using an analog ammeter

Potentiometer

A

You can; the class can……..

Crocodile clips

• Take readings and quantify the resistance changes. • Blow on the glowing rod and observe what happens to the current. • Try leads of different length and hardness.

by JaneYoung, Janette Busch, Peter Smith and Jan McGaw. Published by Triple Helix Resources Ltd: triplehelix@slingshot.co.nz, 246 pp, RRP $46.95 (incl GST and P&P). Reviewed by Heather Meikle, Palmerston North Girls’ High School. Are you struggling to remember how to clean a microscope? What to feed tadpoles? How to use algae in jelly balls? Then the Biolab Sourcebook will provide the answers. Designed to support science teachers, science technicians, lecturers, teacher aides and tertiary students in New Zealand and Australia, the Biolab Sourcebook contains a wealth of information. Throughout the text, the authors demonstrate their vast experience as science educators and technical support staff. In the first section entitled, ‘Working in a Laboratory,’ they state:“Teachers need to try to plan ahead – technicians have to try to be as flexible as possible. Tensions can develop if either side feels put upon,” showing that the

writers have a deep understanding of both roles in a science environment. Written in a clear, concise style, the manual offers a wide range of useful material. For many topics there are references to relevant websites. The authors show their awareness of animal ethics, conservation concerns and health and safety issues. They cite the need for permits, ethics approval and also note potential health and safety risks. In addition they provide the necessary contact details for the appropriate organisations. This book is an excellent reference for science teachers, technicians and teacher aides. It has those key tips that make experiments successful and exciting. Every teacher should have a copy. I will be keeping my Biolab Sourcebook close at hand and dipping into it as I plan units and work through my teaching programme.

bookreview

The Biolab Sourcebook – a manual for science teachers and technicians

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chemistry

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PGOIL

by Suzanne Boniface

If the number of workshops at recent chemistry education conferences is anything to go by, Process Oriented Guided Inquiry Learning (POGIL) is becoming a buzzword in chemistry education. POGIL was originally designed in response to the need to develop alternative teaching methods in higher education that would promote greater student involvement in class and engage them more in their learning (Ref Hansen). This meant finding an alternative to the didactic lecture where the teacher attempts to impart the knowledge from his/her head into that of the students’. In a POGIL classroom students work in teams on specifically designed activities that promote mastery of chemistry, encourage understanding of chemistry ideas, and the development of skills in the processes of learning, thinking, problem solving,communication,teamwork,management, and assessment. A POGIL activity is designed to develop understanding by encouraging learners to be actively involved in restructuring information and knowledge. This is done through a three stage learning cycle that involves exploration, concept formation, and application. In the exploration phase, learners are given a model to examine or a set of tasks to perform that encompasses the learning objectives. Students maybe a given a series of questions to encourage them to explore the model or tasks through critical thinking. The concept formation phase furthers their understanding and uses questions that guide them to make conclusions or predictions. This phase could also involve further exploration of the model

so that students develop an understanding that helps then identify the significance or usefulness of the model. Finally, in the application phase students undertake exercises, problems or maybe research where they can use their new knowledge. POGIL activities are now available online for secondary school classrooms. They can be downloaded from curriculum resources at: http://new.pogil.org/. All the resources are available free for one year from the time you register. In return for these free resources you are expected to provide feedback regarding the effectiveness of the materials, and suggestions for improvements. Some of the material found here could be adapted for use in Year 11 science classes (e.g. Atoms and their Isotopes) while much of it could be useful in Year 12 and 13 chemistry classes. Teachers’ notes are also available. (Please note: when filling out the form to access the teachers’ notes from New Zealand it is necessary to add zeros into the telephone numbers and post codes to give the required number of digits.) For senior chemistry classes it is also worth checking out the Foundations of Chemistry Downloadable Activities, as a number of these could be adapted for use at this level. Some recommended topics from the High School series include: Balancing Chemical Reactions, Net Ionic Reactions (includes solubility rules), Organic reactions, Equilibrium and Le Chateilier’s Principle, and Introduction to Voltaic Cells. Ref: Hansen, D. M. Instructor’s Guide to Process–Oriented Guided–Inquiry Learning. Pacific Crest 2006

new look and name for ChemNZ

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From 2009, the chemistry education journal published by the NZ Institute of Chemistry will be called ChemEd NZ. The new title better reflects the target audience of the publication, and will also reduce confusion between it and the sister publication Chemistry in New Zealand. In addition, the journal will have larger pages – more suitable for including illustrations and allowing a more modern looking and easier-to-read format. ChemEd NZ will now be based in Wellington. The NZ Institute of Chemistry (NZIC) has appointed Dr Peter Hodder to edit the journal. A geochemist, Peter also has strong interests in science education and was involved in setting up the Exscite interactive science centre in Hamilton during the 1990s. An editorial board based at Victoria University of Wellington is being established that will assist him in locating contributions and providing comment on submitted articles. The content of the journal will include: • Aspects of recent chemistry research presented with a minimum of jargon that is anticipated to extend and enhance the knowledge base of chemistry

educators, and which may provide contexts for teaching. • Educational ideas and approaches that can be applied to chemistry education. • New views on chemistry education. • Ideas and new approaches that teachers have found work well. Other articles already promised provide an historic or social context for concepts and ideas that educators use. One example is an article on Mossbauer spectroscopy which provides an insight into the life of one of the youngest Nobel prize winners, and touches on ideas about electron distributions – that are central to chemistry; and ideas about magnetism and the Doppler effect – that are important to physics. ChemEd NZ won’t be all serious; expect some diversions – cartoons, crosswords and the like. And we’d like to know what you think too. For further information contact: chemistry@hodderbalog.co.nz


NZ

science teacher

The Earth orbits the Sun at just the right distance to keep surface water liquid rather than frozen solid, or as water vapour, in comparison with other planets such as Venus and Mars. Studying the Earth as a Goldilocks planet is an interesting way for students to learn about the conditions necessary for life on our planet. Students can also consider the possibility of life in other parts of the solar system and the universe. Below is an exercise idea for Year 9–10 students. However, the Goldilocks planet idea can readily be adapted for more senior classes. Until recently it was assumed that planets just had to be in the Goldilocks zone for liquid water. Now, it is realized, other conditions also need to be right such as a planet’s mass, atmosphere, composition and the way it orbits its nearest star. All these influence whether the planet can keep liquid water on its surface, and it is possible that life could exist on many more planets than once thought. For example, the greater a planet’s mass, the more atmosphere it can hold onto. Computer simulations have shown that a planet further away from its star than expected can hold onto liquid water on some part of its surface, for part of the year, if it has a greater axis tilt and speed of rotation (compared to Earth). Heat can come from the nearest star but also internally from tectonic forces. Also, planets with non-circular orbits move towards and away from their star in the course of an orbit. As a result, they are stretched and squeezed by the gravitational pull of their star, which causes enough friction in their interiors to generate heat and melt water. This could even cause volcanic activity which would produce more gases for an atmosphere. Reference and with thanks to New Scientist: http://www. newscientist.com/section/space then scroll down to the Why the universe may be teeming with aliens link.

The Goldilocks planet – an exercise Conditions on Earth can be compared with the planets that are our closest neighbours. Certain gases in our atmosphere help to heat up our planet. This is because they let through visible light (otherwise we couldn’t see) but act as a barrier to outgoing heat. These are called greenhouse gases because they function much like the glass plates found on a greenhouse used for growing plants. The Earth’s atmosphere is composed of gases, such as carbon dioxide (CO2) and methane (CH4), of just the right

by Jenny Pollock

types and in just the right amounts to warm the Earth to temperatures suitable for life − the greenhouse effect. We can see the effect of greenhouse gases by comparing Earth with its nearest neighbours: Venus and Mars. These planets either have too much greenhouse effect or too little to be able to sustain life as we know it. Mars and Venus have similar types and amounts of gases in their atmosphere, except that: Venus has an extremely dense atmosphere, so the concentration of CO2 is responsible for a ‘runaway’ greenhouse effect and the surface is very hot. Mars has almost no atmosphere; therefore the amount of CO2 is not sufficient to warm up the surface and so the surface temperature is very low. Also, Mars is much further away from the Sun than is Venus. Earth has a very different type of atmosphere. Our atmosphere has much less CO2 than Venus or Mars, and our atmospheric pressure is close to midway between the two. Refer to the table below and answer the following: 1. Which two gases has Earth got a lot more of? 2. Which gas has Earth got a lot less of? 3. Make a comparison between the surface pressure on each planet and the actual surface temperature. 4. Complete the table above by calculating the temperature change for each planet due to greenhouse gases. (Hint: add together the bottom two rows). 5. Using the data from the table above, draw a conclusion as to why life can live on Earth. 6. Why is Earth called the Goldilocks planet? Many scientists believe that the composition of our atmosphere is due to the presence of life. Life keeps the Earth’s atmosphere in balance. If life were to completely disappear, eventually our atmosphere would come to closely resemble that of Mars or Venus. Only with life continually producing oxygen through photosynthesis and removing and re-circulating CO2 does the Earth’s atmosphere remain fairly stable. This exercise is adapted from Project Learn at: http://www.ucar.edu/learn/1_1_2_1t.htm For further information contact: jenny.pollock@xtra.co.nz

Venus

Earth

Mars

Carbon dioxide (CO2)

96.5%

0.03%

95%

Nitrogen (N2)

3.5%

78%

2.7%

Oxygen (O2)

trace

21%

0.13%

Methane (CH4)

0

0.002%

0

Surface pressure relative to Earth (bars)

90

1

0.007

Major greenhouse gases (GHG)

CO2

H2O, CO2

CO2

Temperature if no GHG (˚C)

-46

-18

-57

Actual temperature

477

15

-47

Temperature change due to GHG

+523

+33

+10

science/PEB

Earth as a Goldilocks planet

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professional development Robyn Eden, Queen Margaret College,Wellington The role of the science technician is well known and appreciated by the teachers they work with. The majority of technicians in New Zealand work in a sole charge role, working within all areas of the science curriculum. Our technicians are very resourceful and able to turn their hand to a variety of tasks, and have the ability to come up with innovative ideas to assist teachers in their classrooms/ laboratories. Yet the position can be stressful, particularly at assessment time when the technician can be preparing equipment for assessments as well as catering to the needs of other teaching staff. To ensure that the technician can continue to perform to a high standard, they need the support of their peers and to be enthused with new ideas. Professional development is crucial for this to happen and the New Zealand Electrical Institute Inc (NZEI) agreement for support staff does allow for time to be made available for professional development. The biennial conference for technicians is an invaluable place for technicians to meet and share ideas – the next conference is being held in Auckland in 2009. However, technicians do need to meet regularly in small cluster groups for support. Throughout the country there are groups who meet on a regular basis to share knowledge and ideas. Some of these groups have been running for over twenty years and others have only started in recent years. All the groups are well supported by their local technicians, with attendance at meetings dependent on the needs of the schools at the time of the meeting. The majority of these groups meet at least three times a year, usually in the morning, with local schools taking turns at hosting the meetings. Some groups meet outside of school hours, some regions hold an all day event once a year which is attended by technicians from throughout the local province. Most regions do not charge schools for the meetings but do have a charge for all day meetings. Wellington is the

only region that carries a charge each year to cover photocopying and postage of a local newsletter which is put out four times a year with information from meetings. It must be remembered that due to the remoteness of some schools, it is often difficult for the technician to get to a meeting and this is where attendance at the conference can be so important for the technician. The cost of travelling to conferences, or to a regional meeting, can be expensive, but support from a Head of Department could help ensure the costs are met from the school’s professional development budget. While the local meetings vary from region to region, there is a common thread to them all: fire safety, code of practice compliance, new equipment, and equipment maintenance – they are all areas which have been covered by almost every region. Perhaps one of the single most important components to these meetings is the sharing of ideas between technicians. All of these ensure that the technicians know what is going on and can pass on this knowledge to their schools. Technicians at low decile schools find that the support they receive from other technicians is vital. Technicians organise their own professional development and as such it must be supported by both the technicians and their Heads of Department. It is in a school’s best interest to have staff that are up to date with knowledge and kept enthusiastic about their role. It behoves the Head of Department to encourage their technician(s) to attend any professional development that is available as it means they then have a knowledgeable technician. If you or your technician is unaware of a local group, below are the contacts for local groups. Although most regions have local groups, some don’t appear to have one, so if there is a group operating in your region and it is not recorded here, please contact Robyn Eden, email: robyn.eden@qmc.school.nz so your details can be recorded.

Technicians groups

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East Auckland: Florinda Petterson South Auckland: Beryl McKinnell Bay of Plenty: Dana Payakovich Hawke’s Bay: Netta Brown Taranaki: Mary-Ann Stretton Wanganui: Nic Salt Wellington: Robyn Eden Tasman/West Coast: Sheryl Fitzsimons Christchurch: Alan Smith Central Otago: Georgie Goodall Dunedin: Margaret Woodford

email: fpetterson@sacredheart.school.nz email: bemckinnell@papatoetoehigh.school.nz email: dpayakovich@tgc.school.nz email: nettab@ths.school.nz email: mas@spotswoodcollege.school.nz email: nsalt@collegiate.school.nz email: robyn.eden@qmc.school.nz email: sheryl.fitzsimons@ncg.school.nz email: smitha@papanui.school.nz email: goodallg@mtaspiring.school.nz email: margaret.woodford@kvc.school.nz


Biolive 2009

Transformation and Change 5 to 8 July 2009 University of Otago, St David Lecture Theatre Complex This conference will be held in conjunction with the annual meeting of BEANZ (Biology Educators of New Zealand) and will be hosted by the University of Otago. Nationally acclaimed biological scientists will present keynote speeches on the theme ‘Transformation and Change.’ Conference delegates will be able to participate in a wide range of workshops and fieldtrips in anthropology, biochemistry, botany, marine science, microbiology, physiology and zoology. There will also be a focus on updating current thinking on teaching and learning processes for the 21st century learner.

PROFESSIONAL DEVELOPMENT IN PRIMARY SCIENCE 2009 Dates Dunedin – 14th & 15th April • Christchurch – 16th & 17th April Wellington – 20th & 21st April • Auckland – 23rd & 24th April For teachers who are motivated and interested in: • developing active learning strategies to enhance children’s learning • the importance of providing contextual science experiences: science in a learner’s world • reflecting on current trends in science teaching and relating it to their own practice • taking part in practical workshops that explore the theme of the conference • identifying explicit links between teaching and learning in science education and the key competencies and values

For further information contact the conference convenors: kate.rice@otago.ac.nz or karyn.fielding@otago.ac.nz

National NZIP Conference incorporating

The Science Technicians’ Association of NZ Conference 2009, Auckland ‘Earth, Wind and Fire’ 7 to 9 October 2009

This Conference will appeal to all school science technicians, and also some technicians from tertiary institutions (such as Polytechnics) For further information contact the Convenor, Beryl McKinnell bemckinnell@papatoetoehigh.school.nz

CONSTANZ ‘09

NZASE Conferences 2009 Primary Science Conference

Dunedin (14 to 15 April); Christchurch (16 to 17 April); Wellington (20 to 21 April); Auckland (23 to 24 April).

Biolive 2009

Transformation and Change, University of Otago, Dunedin Date: 5 to 8 July 2009

ChemEd 09

University of Canterbury, Christchurch Date 5 to 8 July, 2009

NZIP incorporating Physikos 09 University of Canterbury, Christchurch Date: 6 to 8 July, 2009

CONSTANZ 09

Auckland. Date: 7 to 9 October 2009

Physikos ‘09

The 14th National NZ Institute of Physics Conference, incorporating Physikos, the NZ Physics Teachers’ Conference

6-8 July 2009

University of Canterbury, Christchurch Energise your physics teaching with three days of ideas, stimulation and interactions! For further details visit: www.nzip.org.nz

9 ChemEd 09 0 Ed

m e h C emEd 09 Ch d 09 E m e Ch emEd 09 Ch ‘Chemistry on the Edge’ 5 to 8 July, 2009

University of Canterbury, Christchurch For further information contact: Richard Rendle Tel: 03 3597275 Fax: 03 3597248, email: rendle@xtra.co.nz



NZASE #120