Teach-Primary-Issue-19.1

• Why do you think certain ingredients (like baking soda) are important in toothpaste? • Which toothpaste recipe was the most effective? Why do you think so? What is your proof? • How could the recipes be improved? • Why is peppermint a common toothpaste flavour, and do you think other flavours would work? • How important is the colour of toothpaste? Does it affect how likely people are to use it? permanent marker dot to simulate dirt, get the teams to test their formulations in turn. At this stage it is essential to discuss fair testing, e.g. ensuring that the toothpaste is applied with the same motion, same approximate pressure and for the same duration. Following each test, those children not in the group whose formula is being tested should make observations (perhaps on a pre-devised numbered scale) of how well the formulation stayed on the toothbrush, its smell, and the effectiveness of the cleaning (any changes to the permanent marker dot). 3 | REVIEW When all the tests are complete, the teams should comparatively tested against other teams’. Emphasise the need to capture the quantities of the ingredients in their formulations, so that it would be possible for the toothpaste companies to replicate the most successful recipe. It is also important to discuss that they may adapt their formulation – e.g. adding more glycerine if it is too dry – but that they should also record any amendments, and the quantities used. 2 | TEST Once each team has formulated their toothpaste, ask pupils to work collaboratively to test its effectiveness. Using white tiles, old plates or saucers (one per team/formulation) marked with a large, • Given enough time (and ingredients!) you could challenge the children to take a second pass at their formulation, based on the feedback from other groups, to improve the impact of the toothpaste recipe. This would be an authentic way of modelling the scientific process of responding to and building upon the outcomes of experiments. • You could also use the outcomes of the investigation as the context for some purposeful writing. Perhaps pupils could write to a toothpaste company, sharing the results of the investigation, or devise a persuasive marketing campaign for their own brand of toothpaste. • This investigation could also launch a broader unit of learning focused on personal hygiene and caring for oneself. EXTENDING THE LESSON then look at the combined investigation outcomes, considering: How well did each toothpaste remove stains? Which seemed most effective? Did it smell fresh and pleasant? Which was the most appealing of all? Did it stay on the brush during use? Which seemed to have the best consistency? Once each group has drawn their conclusions, ask them to present their findings to the class. You can collate these outcomes to allow for later comparison and discussion. This is an opportunity to introduce scientific debate and discussion, and for the children to apply their communication skills, sharing their judgements and discussing potential improvements to each formulation. With all the groups having provided their feedback, you can then lead a class discussion based on the outcomes and comparative effectiveness of different formulations. What worked best? Were there any surprising results? To fully conclude the investigation, it would then be beneficial for each team to reflect on the feedback they received, identifying the strengths of their recipes and suggesting justified amendments that they might make to future concoctions. Marc Bowen is a deputy head and primary teacher in South Wales. He is always keen to engage in professional dialogue, sharing ideas and experiences for use in the classroom. He welcomes any responses to this article or further questions through his email bowenm43@ hwbcymru.net “Help pupils realise that mixing potions isn’t just a fun activity, it’s what scientists do all the time” USEFUL QUESTIONS www.teachwire.net | 73