Wow! But Why? - Sample chapters

(or, why you’ll never see elephant’s toothpaste in my classroom)

Years ago, I worked with a colleague who had very strong opinions about pretty much everything, and usually wasn’t afraid to share them. Often in staff meetings, when some new method of data collection or a new ‘non-negotiable’ for our classroom displays was pitched, you would hear his voice asking, ‘Why, though?’, always in the same frustrated tone. For me, it became so linked to the unnecessary hoops that teachers have to jump through that I now hear that voice asking that question every time I come up against something similar when teaching or working to support other teachers.

Now that I spend a lot of my time learning about and working in science education, I’ve found this little voice creeping in more and more when looking at ‘wow-factor’ science activities. The straw that broke the camel’s back was seeing the infamous ‘Elephant’s toothpaste’ experiment recommended as a National Science Week activity by three separate sources on the same day. We all have pet hates; things that make us unreasonably angry. ‘Elephant’s toothpaste’ is mine.

To carry out this activity, a selection of chemicals is added to a conical flask or bottle. One of the ingredients is a catalyst, meaning that the resulting chemical reaction from mixing the different chemicals happens very quickly and creates a foamy substance that looks like largescale toothpaste (if you use your imagination!). The reaction itself is, admittedly, quite exciting and will definitely elicit shrieks and giggles from the audience.

Why, though?

The activity doesn’t have any relation to any content in most primary curricula. It is certainly not a practical activity for children, as it is usually done as a demo due to the unsafe nature of the chemicals and reaction involved. It is not an experiment or an enquiry, as there’s no question to investigate. And, to top it off, some of the ingredients needed are quite difficult to source, so it’s not even an easy one for teachers to set up. There’s also the worrying potential for this activity to reinforce the stubborn stereotype that science is all about crazy old men with frizzy hair and lab coats mixing together brightly-coloured chemicals and making explosions in labs.

The activity will no doubt create a ‘wow moment’, but with so much content to teach in a packed curriculum, can we really justify spending time on a wow that doesn’t have a why behind it? It is increasingly being noted that, often, science activities are delivered because they are exciting, rather than having the aim of teaching a specific skill or concept, and this results in children remembering the activity but being unable to recall any learning. For example, in the Ofsted 2021 Research Review of Science, it is said that ‘teachers can often prioritise “wow” moments without clear reference to any curricular goal’ and that, although pupils enjoy practical work, ‘research suggests that this does not, by itself, foster long-term personal interests in the subject’1. It is also noted, in the recent report 10 Key Issues with children’s learning in primary science in England that, too often, ‘Children experience “fun” science activities that fail to deepen or develop new learning’, resulting in them being able to retell the ‘magic moments’, but unable to explain what they have seen or the concept that they were exploring2.

This is something that I have also seen mirrored in my own experiences and from working with other teachers, and it is devastating to find that, when so much effort has gone into an exciting learning experience, no actual learning took place.

Teachers are a wonderfully enthusiastic and creative bunch of people. This means that they are always looking to make their lessons engaging, exciting and memorable; this is absolutely as it should be and my aim is not to remove those experiences from the classroom. With this book, I hope to answer that niggling ‘Why, though?’ question and provide meaningful learning opportunities attached to ‘wow factor’ activities. This book contains ideas that will help to link not only scientific knowledge, but also ‘working scientifically’ skills, to these exciting experiences in order to give them more meaning and result in more real learning taking place. There are also ideas to link the concepts and phenomena encountered to children’s own lives, as well as illustrating how the science is relevant to the wider world. You will find lots of exciting ideas, some familiar, some hopefully new, that will enhance science learning in your classroom… just not elephant’s toothpaste!

Biology

1.2 Life cycles in the classroom: chicks, caterpillars & tadpoles

The Wow

Commonly carried out towards the lower end of primary, bringing animal life cycles into the classroom is a highly exciting and memorable way to teach children about the ways that different animals change differently over the course of their life cycles.

There are a few different animals that this can be done with:

Chicks

Hatching chicks (or ducklings) in the classroom is one of the more time-consuming (and potentially expensive!) ways of bringing life cycles into the classroom. You will need to either purchase or rent an incubator, then source eggs to go into them. There are a number of companies that offer a rental service, as well as some local farms. It is important to investigate your egg and incubator source before making any purchases to make sure that the animals involved are ethically treated from the beginning to the end of the process, as this does differ from one organisation to another. The incubator will need regular checks to ensure that the temperature and humidity levels are correct and to increase your chances of a healthy brood of chicks. You will also need to think about providing an appropriate temporary home when your chicks hatch, with food, water, space and a heat source –some incubators come with a heat lamp, but not all; make sure that you check this before you make any decisions.

When the hatching has been observed and the chicks begin growing (which they do surprisingly quickly!), you will need to think about where they will go. Companies and farms who offer hatching services generally accept the animals back into their care, although some schools choose to keep some of the birds so that children can continue to observe how they change and to take part in their care. Although relatively arduous to organise and set up, the experience is a wonderful and valuable one for children, who are able to

observe chicks emerging from eggs in real time, then see the wobbly new hatches gain fluffy feathers and start making lots of noise in the classroom!

Caterpillars

As with chicks, there are a number of companies that can provide caterpillars, along with an appropriate enclosure and food source. Over the course of a few weeks, children can observe the caterpillars entering pupas, then emerging as fully-fledged butterflies. These can then be released into the local environment when they are ready. Doing this in the classroom gives children a great opportunity to observe butterflies close up as they are very slow moving when they first hatch, whereas in the outside world they usually move too fast for little ones to get a good look.

Tadpoles

The easiest place to source frogspawn will be your local pond or nature reserve. Care will need to be taken to ensure that their tank is appropriate for their needs. Chlorine can be deadly to tadpoles, so rather than using tap water (which contains very small amounts of chlorine), it may be best to take water from the same source from where you’re collecting the tadpoles, or use rainwater. If you need to use tap water, leave it out to stand exposed to sunlight for one week, which will allow the chlorine to be removed by evaporation. There is a great deal of support online for helping to set up and feed your tadpoles that can be drawn upon to make sure that they are happy. The information from CLEAPSS or SSERC is very thorough, or the Amphibian Ark website also has guidance (www.amphibianark.org). It takes around 6-12 weeks, depending on species and some environmental factors, for frogspawn to develop into frogs. As with butterflies, the adult animals can be released into the wild in a suitable environment (preferably the pond from which the frogspawn was taken) when you have finished observing them in the classroom.

In addition to these animals, another popular activity is inviting a parent with a young baby into school so that children can make first-hand observations of how the baby is different from themselves, and also from adults. This is a particularly valuable experience for children who don’t have younger siblings or family members that they know well.

As with any animal that you bring into the classroom, it is important to think about their wellbeing and ensure that they are safe and content while they are in your care. Make sure that you read as much guidance as possible before bringing live animals into school, so that this can be done ethically and compassionately.

What’s going on?

All living things have a life cycle. This is a series of changes that organisms go through that eventually returns to the starting state. For example, the human life cycle involves being a baby, then a child, then an adult. Adults reproduce and, after a gestation period in the mother’s womb, the life cycle is brought back to the baby stage again. Different types of animals have different types of life cycles.

Mammals – As we humans are mammals, we share the same life cycle as other mammals: baby → child → adult → baby.

The period after fertilisation when the offspring grows in its mother’s womb is known as the gestation period. This is generally longer for larger animals, although there are some exceptions to this rule, humans being one of them. Mammals typically don’t have a lot of babies at once and usually at least one of the parent animals sticks around to raise the babies for a while after birth, although this does differ from species to species. Mammal babies get nourishment from their mother’s milk when they are young. Mammal young tend to look like smaller versions of the adults of the species.

Birds – The bird life cycle has one key difference from the mammal one; they do not gestate in their mothers’ wombs: chick/young bird → adolescent bird → adult bird → eggs → chick.

Eggs that have been fertilised by a male bird of the same species are looked after by one or both of the parent birds until they are ready to hatch. After hatching, most birds are then fed and looked after by one or both parent birds until they are strong enough to fend for themselves. Because of this, birds tend to lay relatively small clutches of eggs. As with mammals, young birds tend to look like smaller versions of their adult counterparts.

Insects – The insect life cycle again has a key difference from those of birds and mammals, metamorphosis: Eggs → larva → pupa → adult → eggs.

Insects typically lay lots and lots of eggs at a time and don’t stick around to raise their young. When the eggs hatch, the first stage of development is known as the larval stage. In the case of butterflies, the caterpillars are the larvae. You may have also seen maggots, which are the larval stage of flies. All insects have this stage of development, including ants, bees and ladybirds, but it is not very well known because we don’t often notice the larvae of these insects. After this stage, the larva will enter a pupa, inside which it goes through significant changes in the process of metamorphosis. This means that, unlike mammals and birds, young insects look completely different to adult insects of the same species. When enough time has passed, the insect will emerge from the pupa in its new form. It is now an adult and can go on to lay its own eggs.

Amphibians – Amphibian life cycles have fewer stages than the others that we have looked at: Eggs → larva → adult → eggs.

In the case of our frogs, frogspawn is the egg stage, tadpoles are the larval stage and frogs are the adult stage. The life cycles of salamanders and axolotls are similar, with the larvae growing new legs as they become adults. The young do look different from the adult of the species so, for many species, metamorphosis takes place to some extent, but they do not undergo the same level of significant structural change as insects. Some, like our frogs, acquire the ability to breathe on land as they grow, but not all do.

The Why

For science learning, being able to observe life cycles in action in the classroom is a valuable experience for children. They will be able to see clearly how animals change as they grow and how this happens in very different ways for different types of animals. It also allows children to practise using the vocabulary associated with life cycles and animal features, and apply it to the processes that are happening in their classroom. It is important to communicate with other teachers in school to make sure that children don’t repeat experiences in different year groups, and are given the broadest possible range of animals to observe during their time in primary school. This activity is also beneficial in developing children’s understanding of the differing needs of different animals and our role in ensuring that they are healthy, happy and well looked after. This applies to both the animals that we are caring for in our classroom and those in the wider world, for which we all have a responsibility.

Often, after the animals have hatched, emerged from their pupae or grown legs, they are returned to a more suitable environment for them and the process of observation ends. If possible, it would be very valuable for children to visit the habitat of the adult animals so that they can make further observations. This is probably not possible in the case of butterflies, but if chicks are returned to a local farm or frogs to a nearby pond, it will be easy to take children to see the animals and witness how they have changed since they left the classroom.

Growing animals in the classroom tends to be carried out towards the lower end of primary school but, as children typically learn about life cycles further up in school too, there is no reason why older children cannot also take part in observing the changes. In fact, these pupils could be challenged with taking closer, more systematic and more accurate observations. For example, they could take measurements of the mass of an egg before it goes into the incubator, and then of the hatched chick after certain amounts of time have passed (very carefully, of course!). Alternatively, if children have had experience with these more familiar animals and life cycles in early primary, they could then draw on this to formulate questions about other life cycles, which can be answered through research. For example, do all insects go into pupae? Do penguins have the same life cycle as chickens? Are there any mammals that lay eggs? Which animal has the shortest life cycle?

Having animals in school tends to be quite a significant event, so it is likely, if you have them in your classroom, that you will be getting visits from other classes. This opens up the possibility for children in different year groups to revisit and consolidate the learning about animals that they have been doing in their own classrooms. For example, observing the different types of animals means that they can think about the different ways of classifying these animals, and seeing the way their temporary habitats have been set up will prompt them to think about the differing needs of different animals for survival.

In the Real World

Depending on what kinds of animals you are observing, there is a wide range of science careers that could be linked to this activity:

Phenologists – scientists who learn about life cycles;

Ornithologists – scientists who study birds;

Entomologists – insect scientists; and

Herpetologists – scientists who learn about reptiles and amphibians.

Children could learn about the roles that these scientists have not only in studying their respective animal types, but also the work that they do to support conservation and ensuring that these animals’ environments remain safe and suitable places in which their life cycles play out. A visit to a local wildlife reserve would allow children to observe a range of familiar animals in their habitats and reflect on how they could perhaps make their immediate environment more friendly towards wildlife populations.

Health and Safety Notes

Children must wash their hands before and after handling any animals

Always supervise children when handling animals

Tables on which animals have been studied should be cleaned immediately afterwards with hot water and detergent

Ensure that any animal enclosures are regularly and thoroughly cleaned by an adult

Depending on which animals you have in the classroom, care may need to be arranged for them over the weekends

Check with parents and carers for any allergies to eggs, the chicks or their bedding before bringing these into the classroom

Check with the supply company that you are using that the eggs have been tested for commonly known diseases that can be passed through eggshells, such as E. coli and salmonella

Chemistry

2.6 Easy ice cream

The Wow

Anything involving food, especially food that children can actually eat after the activity, is always going to be exciting! This activity allows children to make edible ice cream in the space of 10-20 minutes using some easy-to-find ingredients and equipment.

To make one serving of ice cream, you will need:

Ingredients:

250 ml single cream or milk (full fat works best)

1 tbsp caster sugar

1/2 tsp vanilla extract (other flavourings can be used for a different taste)

Lots of ice

75g salt

Equipment:

Small resealable plastic bag

Large resealable plastic bag

Measuring equipment (measuring jugs/cylinders, scales, etc.)

Oven gloves or a towel.

Instructions

First, add your milk, sugar and chosen flavouring to the small resealable bag. Squeeze out as much excess air as possible and seal the bag tightly.

Add the ice and salt to the large resealable bag and give it a shake to combine both substances. Put your sealed-up smaller bag into the large bag and seal the top tightly.

The only thing you need to do now to make ice cream is to shake and shuffle the bag vigorously for around 10 minutes (more or less time may be needed depending on the specific ingredients you use). The outer bag will get very cold while you’re doing this, so make sure that you have a towel or some oven gloves to hand to protect your skin from the freezing temperatures.

After a few minutes have passed, you can open up the bags and check to see how your milk mixture is changing. When it is ready, all you need to do is to open up the bags and empty your ice cream into a bowl to be eaten, adding some tasty toppings if you want!

What’s going on?

In very simple terms, the milk mixture begins to freeze (or solidify) because of the cold ice, and changes state to become a solid. There is a lot more going on in this process though, much of which may be too complicated for primary-age scientists, so careful thought will need to be given to how you present this activity to children and how the background knowledge is explained.

First, we need to know a bit about states of matter. Materials are made up of tiny pieces that we can’t see, called particles. In solids, these particles are very close together, arranged in a regular way and are held together by forces of attraction between the particles. In liquids, the particles are still quite close together, but they are arranged randomly. Particles in liquids have enough energy to move around and break free from the forces holding them together, which is why liquids can be poured and take on the shape of the container that they are in. It is important to remember that children following the National Curriculum for England are not required to learn about how particles behave or are arranged in solids, liquids and gases, so careful thought will need to be given to whether it is appropriate or not to talk about this concept with children.

We also need to know about changes of state to explain what is going on here; when liquids cool down enough, they freeze and become a solid. This is because the particles slow down as they cool and so become less able to move around each other. They are pulled into a regular pattern and become solids. This happens to different liquids at different temperatures, with the temperature at which they solidify being called their freezing point.

The freezing point of pure water is 0˚C. However, when salt is added, the freezing point drops a few degrees. This means that the ice and salt in the outer bag is above its freezing point and begins to melt. The heat energy for this is drawn from the milk mixture in the inner

bag, meaning that this mixture cools and the water contained within the milk begins to solidify, forming ice crystals and creating what we know as ice cream.

As you can see, this is complicated science requiring knowledge that is beyond the content of most primary curricula; if you decide to carry out this activity, make sure that you have thought about how it will be explained to children so as not to confuse them, introduce misconceptions or make it difficult from them to learn the foundations of changes of state, which will need to be solid for them to build on in future years.

The Why

This activity is tricky to link with most primary curricula because, as mentioned above, the science involved is beyond the typical expectations for children of this age. While there is an element of changing states, the reasons behind why salt is needed to make the process work are quite complex and can confuse children, particularly if they are new to the concept of changing state and are just becoming secure in their initial understanding. You may wish to keep it simple and use this as a demonstration of a liquid becoming a solid, just explaining that the ice mixture is cold enough to freeze the liquid milk mixture in the inner bag, turning it into a solid.

Children tend to have observed far more examples of melting than they have of solidifying in their own lives (butter melting on toast, chocolate melting in their hands, ice lollies melting on a hot day), so there is some value in this activity as a chance to observe something freezing first-hand.

Children could investigate the differences between liquids with different fat content, including non-dairy products like almond milk, comparing how easily they become ice cream and how tasty the finished product is. There are some great potential links to maths and design technology here, as children could be asked to weigh up the different aspects of what makes the ‘best’ milk product to use; cream may make a tastier ice cream, but it is more expensive and unhealthier than milk, and less environmentally friendly than oat milk. Keeping to a healthy eating theme, children could also investigate how low the sugar content can get before the ice cream becomes less tasty, or whether sugar can be substituted for flavourings. With these investigations, there are opportunities for children to practise their skills of taking accurate measurements, planning an investigation, recording and presenting results and coming to conclusions based on the evidence that they have gathered. There is also potential for children to explore the difference between carrying out the process with and without salt, but this will require more complex scientific understanding to get to grips with than is necessary, so should only be used with caution.

In the Real World

Providing they live in a climate cold enough for freezing temperatures at least some of the time, children will be most familiar with the phenomenon of ice behaving differently when mixed with salt in wintertime when salt is added to roads and pavements to make them less slippery. The salt lowers the freezing point of the ice, meaning the temperatures in the surrounding environment are no longer cold enough to keep it frozen and it melts. This is helpful because there is more friction on wet surfaces than there is on icy ones, making it safer for people and vehicles to move around. Making this comparison will require some explanation of the complex science discussed above, though, and so will need to be done carefully.

Alternatively, children could find out about the processes used to make ice cream in the real world. Ice cream-making machines used in homes work on a similar principle to what is done here; the ingredients are added to a central container, around which there is a much colder one, then churned in a similar way to the shaking of the bag that is done here. On a larger scale, children could learn about the work of food scientists and food technologists who develop different flavours and textures of ice cream, and the manufacturing processes that go into creating large amounts of it. They could compare their simple list of ingredients to those on the packaging of their favourite brands and reflect on why (or if) so many different ingredients are needed in the ice creams that they buy in the supermarket.

Health and Safety Notes

As with any food preparation, ensure that children wash their hands with soap and water first

Check for any allergies, intolerances or dietary restrictions before allowing children to eat their ice cream

This activity can get very messy – make sure that any spills are cleaned up promptly to avoid any slips, trips or falls

Physics

3.9 Teddy parachutes

The Wow

This is a really simple activity, with lots of scope for practical investigation that children will love because it involves their toys!

All you will need are some small toys such as mini teddies or toy soldiers, some string and materials to use as parachutes. Good options for this are different types of paper, card, thin, flexible plastic, fabric and aluminium foil. There are many different ways to approach the activity, but you could start by asking children to create a simple parachute by cutting out a square of the material of their choice, using sticky tape to attach a piece of string to each of the four corners, then tying these strings onto their small teddy or toy to create a parachute for them. This can then be dropped from a height to see how the parachute performs.

What’s going on?

The toy falls to the ground because of the force of gravity, which pulls everything towards the centre of the Earth. As it falls, the force of air resistance pushes back against it. This is a type of friction that slows down the fall slightly. Objects with smaller surface areas encounter less air resistance, and those with larger surface areas will be met with more. You can see this in action by dropping two identically-sized pieces of paper from the same height, with one kept flat and the other scrunched into a ball. The flat piece will fall much more slowly, because it has more air resistance pushing back on it than the piece that has been squashed into a smaller shape. When we add a parachute to our skydiving toy, it will have a much larger surface area, will encounter much more air resistance, and so will fall more slowly. This is the same way in which real parachutes work.

This is a great activity to give children the opportunity to see air resistance in action, slowing the fall of a toy significantly. There are excellent links with knowledge about forces as well as some potential links to properties of materials, as using different materials to make the parachutes will result in different speeds of fall for the toy.

There is also much potential for children to practise a wide range of ‘working scientifically’ skills while carrying out this activity, as there are so many possible variables that they could investigate:

How does the size of the parachute affect the speed of the fall?

Which material is the best to make a parachute?

How does the shape of the parachute affect the speed of the fall?

Does the shape of the parachute matter if the overall area is kept the same?

Does the length of the strings have an effect on how the parachute falls?

Depending on which skills you would like children to focus on, you could offer different levels of support for them to come up with their own scientific question and plan an investigation to find an answer. Alternatively, they could have a structured investigation to follow, and focus on using their understanding of air resistance to come up with a reasonable prediction for what they will find, on gathering accurate (perhaps repeated) results, on finding the best way to represent their data or on using their results to come to a conclusion that answers their investigation question.

Because children are likely to be dropping their parachutes from a relatively low height, the drop might happen too quickly for them to get an accurate measurement. If this is the case, you might want to give them electronic tablets with cameras that can record the action, allowing them to watch the videos back to get a better idea of how long different parachutes took to fall to the ground.

This activity could also be run as a design and technology project, whereby children are tasked with designing, making and evaluating a parachute for a given client, perhaps a skydiver who wants to be able to land safely after jumping from a plane, or a space agency that wants a parachute that will allow some equipment to come to a slow and safe landing after falling to Earth from space.

In the Real World

The parachutes that we have made for our teddies work in the same way as real ones – which have just been engineered more precisely. Children will probably be familiar with the use of parachutes for skydivers, or as a safety measure on planes, but there are many other uses for this science knowledge that they could find out about. Parachutes are important for spacecraft so that they can make a safe landing after approaching a planet at speed. This is true for astronauts returning to Earth after time in space, as well as being the case for research equipment, such as the Mars Rover, which needs to be able to make a safe landing on its destination planet so that equipment doesn’t get damaged.

Learning more about the different purposes of parachutes can also help children to understand that air resistance doesn’t only act in one direction; it does not just act on falling objects, but on all objects moving through air. They can see this in action on parachutes deployed to slow down drag racing cars when races are over, and on resistance parachutes worn by runners who want to make their training harder by increasing the amount of air resistance that they have to run against.

Health and Safety Notes

Do not allow children to climb unsafely or to unsafe heights to drop their toys and parachutes

Earth Sciences

Making fossils

For this activity, children can make their own fossil models using craft materials.

You will need:

Card cups (plastic cups will work too, but are more fiddly)

Modelling clay or plasticine

Plaster of Paris (ready-prepared and mixed with water by an adult)

Small hard objects to make imprints, such as shells or small toy animals (toy insects work well)

Instructions:

1. Push down your modelling clay into the bottom of the cup so that it is around 2-3 cm deep.

2. Firmly press down your shell or toy animal so that a clear imprint is left in the modelling clay, then take it out again.

3. Pour Plaster of Paris into your cup so that the imprint is fully covered. You can either just fill the imprint or add another centimetre or so of Plaster of Paris depending on how you’d like your finished fossil to look.

4. Leave your model to set. This will take around 24 hours and will depend on how deep your layer of Plaster of Paris is.

5. Once it has set, tear away the card cup (or cut it away if you’re using plastic) and carefully peel off the modelling clay. You will be left with a fossil replica of your shell or toy. This can be painted if you would like to make it look more realistic.

What’s going on?

This process has some similarities to the real process by which fossils are created, but there are a few important differences that you need to know about.

Fossils are remains or traces of living things that have been preserved by natural processes. There are different types of fossils, including:

Trace fossils: these are fossils that show traces of a living thing, rather than the living thing itself. Footprints, trails and coprolites (fossilised poo!) are all examples of trace fossils; and

Body fossils: these are fossilised remains of plants and animals. This type of fossil allows us to see what the organism looked like when it was alive.

For a fossil to be formed, some very specific things need to occur, meaning that it is actually very rare for living things to become fossilised. There are a few different ways in which fossils can be formed, including:

Mould or impression fossils: these are formed when sediment fills imprints left behind, either from living things that have died and fall to the ground or sea floor, or when a heavy animal has walked through mud and left footprints. This type of fossil formation is probably the closest process to our home-made fossils;

Cast fossils: this is the type of fossil that most people are familiar with, as they make up the impressive dinosaur skeletons that can be seen in museums. After a plant or animal dies, the soft parts of its body decompose, leaving the hard parts, such as skeletons and shells, behind. Over time, these can become buried by small particles of rock, called sediment. As more layers of sediment build up on top, the pressure causes the layers underneath to become hard and turn to rock. The organism’s remains then start to be dissolved by water seeping through the rock. Minerals in the water fill the mould left by the remains, leaving us a rock replica of the original living thing. This is a very slow process, taking at least 10,000 years for a fossil to be formed; and

Amber fossils: you might be familiar with these from famous dinosaur movies! This type of fossil is formed when a living thing, such as an insect, gets trapped in liquid tree sap. This then hardens around the organism, becoming amber and preserving the remains inside.

The Why

The most straightforward way to link this activity to primary science learning is when learning about fossils: how they are formed and how they give us evidence about life on Earth millions of years ago. It will need to be delivered carefully to prevent children from picking up any misconceptions about how fossils are formed. Make sure to draw comparisons between the real process and what we are doing with our model at each step of the way. As with all cases where models are used to represent scientific ideas or phenomena, it is a good idea to discuss with children the ways in which our fossils both are and are not like the real thing. If they can clearly explain the similarities and differences, then it is likely that they have a good understanding of the real process.

Aside from reflecting on the use of models in science, there are not really any scientific skills involved in carrying out this activity. For this reason, it might be better if this activity is carried out as part of an art/craft lesson rather than devoting valuable science curriculum time to it.

In the Real World

Many children are naturally interested in dinosaurs and other prehistoric life, so it is unlikely they will need extra encouragement to be excited about this topic! If you are lucky enough to be located near an area where fossils are likely to be found, mostly coastal areas, you could take your class out fossil hunting. The study of fossils is called palaeontology and involves skills of observation, identification and classification, and drawing conclusions from available evidence.

Health and Safety Notes

If children get any Plaster of Paris on their skin (either wet or dry), wash it off with soap and water

If Plaster of Paris gets into the eye of any child or adult, it should be irrigated continuously with an eye wash, and medical advice should be sought

Hands should be washed with soap and water after using Plaster of Paris

Plaster of Paris can get very hot when setting; do not allow children to handle the fossils until they are fully set.