Making Science Real

Trying to fit every subject into the already overcrowded curriculum is getting increasingly difficult. Greater depth projects which span multiple areas of learning are often the answer. As well as being more satisfying and motivating for the children (and teachers), they can pick up many maths, literacy and other curriculum objectives on the way, whilst being much more purposeful and relevant to real-life. 

When I asked my Year 4s at the end of the summer term which science activity they had enjoyed the most, the response was almost unanimous: our toothpaste project. The reason? Because it was hands-on, exciting and something that they could easily relate to.

Teeth is one of the topics of study in Year 4 science, but I didn’t want to make 26 sets out of playdough – partly because I wasn’t sure that I would do a good job – so I turned to the excellent CIEC resources as a starting point – Just in case you are not already familiar with these, the Centre for Industry Education Collaboration (CIEC) provides a range of curriculum-linked teaching resources for the teaching and learning of the science curriculum – one of which is entitled ‘Health Drinks and Tasty Toothpaste’.

Observation over time

We started off by testing the impact that different drinks have on our teeth by immersing boiled eggs in a variety of liquids: orange juice, water, coke, milk and coffee. Coffee was chosen by the Year 4s as they wanted to know whether it would stain the egg shell.

We started this investigation on Monday 18th June, which meant it fitted in well with our Great Science Share for Schools event on the following day. Year 4 children were able to take their eggs into the hall to share with pupils and adults from the visiting schools. They created a prediction table which they invited people to fill in – not surprisingly the coke was voted the liquid that would have the most harmful effect.

Over the course of the next week we observed the eggs carefully and recorded any changes. Not unexpectedly, the water had no effect. We were however surprised that the orange juice appeared to have had the worst effect. Coffee had stained the eggshell, as we had anticipated. When the children investigated orange juice, they found out that it had a pH of 4.2, which meant that it was quite acidic.

On reflection, it would have been better to peel the eggs and just leave the shells in the liquid, which would have made them easier to handle. The CIEC resource just suggests using dilutions of vinegar; however, the children wanted to use real drinks.

Linking with history

Everyone agreed that it was important to regularly brush your teeth to remove any sugars that could cause decay. This led onto a piece of research which was set for homework to investigate the history of teeth cleaning.

Some very interesting facts were discovered: –

Inventing our own engineering solutions

As I am always very keen to incorporate an engineering element into our projects, I asked the children, for homework, to continue the timeline by imagining how people would clean their teeth 500 years from now – in 2518. I was not disappointed, as they came up with some really original ideas.

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Next step in class was to test different brands of toothpaste to see how effective they were in removing permanent marker pen off a white tile (scratchiness test).

The children also tested for thickness by trying to shake a blob of toothpaste off the toothbrush. This caused much hilarity and a few accidents on the carpet where the aim had not been quite as accurate as it might.

Arm & Hammer appeared to be the best at removing the pen.
Arm & Hammer also took the most amount of shakes to drop off the toothbrush.

Making our own toothpaste

Of course what all the children had been waiting for was the opportunity to make their own toothpaste. We used the recipe from the CIEC resource adding peppermint essence for flavouring and various food colouring. The key to success was to obtain just the right thickness.

Isaac and Mason added real strawberries to their mixture. Not very practical as the mixture would soon go off, but an interesting idea.

Once the toothpaste was made then it was time for the scratch and shake testing. All of the groups declared that their own brand of toothpaste was much more successful than the real thing.

Linking with maths and literacy

There was a great opportunity now to develop other cross-curricular links, as we decided to think about packaging and marketing our various toothpastes. In maths, we opened up the toothpaste boxes to determine the net we would need to make our own containers. We also looked at the information that was included on each side to make sure that our versions matched.

Next came the development of a name for our toothpaste and associated logo. In Literacy, we examined existing brands and analysed why the names might have been chosen. We decided that it was important that the name reflected the benefits of the product.  There were some thoughtful ideas, ranging from Brush-up through to AquaMint and Magic Shimmer.

One of the packaging designs

The children were certainly very proud of their efforts and keen to promote their products. We were quickly approaching the end of term, so after some initial research into existing toothpaste advertising, I gave each group an iPad and tasked them with using what they had discovered to produce their own TV ads. Considering the searing heat and very limited time frame, I think that their first takes were very commendable (if somewhat over enthusiastic in some cases :))

Here are just a few examples for you to enjoy:

Taking the learning home

Perhaps the most rewarding aspect of the project for me, as a teacher, was when one of my pupils asked to show me a tube of toothpaste that her mum had given her which she thought would be of interest. Iona had heard me talk about Biomimicry – engineers taking ideas from nature – as we had looked at examples earlier in the year and she thought that this product might have links.

She was right. This toothpaste is special because it uses something called ‘bioactive glass’ which contains Calcium, Phosphate and Fluoride. When encountering acid on teeth caused by bacteria metabolising sugars, the glass dissolves quickly raising the pH and releasing calcium phosphate and fluoride ions to minimise damage to the enamel.

Obviously, the glass particles are very tiny, so they do not scratch the teeth. Although this was a very complex subject, it led to a great discussion about how glass is made and questions as to why sand couldn’t be used in toothpaste in the same way. They eventually decided that sand particles would be too big and they would discolour the toothpaste  – quite remarkable I thought for 8 and 9-year olds.

If I return to this topic next year, which I am sure that I will, I would really like the opportunity to take the children to a toothpaste factory. If anyone knows of a suitable venue in the UK – preferably in the North West – please let me know.





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