Comparing Teeth of Carnivores & Herbivores

Objectives

To look at different animals’ teeth and discuss why they are different shapes.

To think of different ways that people and animals harm their teeth.

Resources

Lined paper | Egg shells | A range of different drinks and transparent cups - water, milk, coke, lemonade, orange juice, diet dizzy drinks | Assignment 3

Today's Lesson

Main Activity

Discuss the reason why we have to brush our teeth every morning and evening, and sometimes straight after a meal. Discuss tooth decay with your child. Why do we need to brush our teeth to keep them healthy and monkeys, for example, do not? [Our diet is no longer the healthy pure vegetable and fruit diet that it used to be. We tend to eat a great deal of sugar, even if we do not add it to our food. Much of what we buy has sugar added to it. We also have a tendency to eat sweet foods such as chocolates, sweets, biscuits and cakes, all of which have a great deal of sugar. This sugar feeds the bacteria in our mouths and they produce an acid, which damages our teeth, causing cavities. Animals do not suffer from cavities, as they do not eat the refined sugar that humans do]. Ultimately, the best diet for humans is the same, natural diet as our primate ‘cousins’ eat.

Investigate the question: What is the best drink for my teeth?

Ask your child if they can remember what a variable is (it’s something you can change when testing, that will make a difference to the results).

Watch the Egg School Science Experiment video and discuss the investigation with your child. Explain that the material that makes up an egg shell is similar to that which makes up our teeth, so we can use egg shells to gain data that helps us learn about our teeth in some ways.

Ask your child to identify any elements of ‘fair testing’ in the video - they tested a wide range of liquids / drinks; they mentioned putting the eggs in the same amount of liquid; all eggs were the same size (and probably from the same batch), so the only variable that was being changed was the type of liquid / drink.

Ask your child what they think they should be observing to know what effect the different liquids have had on the egg shells - e.g. colour, a change in texture and appearance, a change in strength of the egg shell.

Make predictions about what effects different drinks will have on the egg shells. What will be worst / best for teeth? Why? Can your child order the drinks based on the amount of damage they will do to our teeth?

Decide which variables need to be kept the same that will make a difference if changed: the amount of egg shell; the shape of egg shell; the amount of liquid; the time the egg shell is left in the liquid; the place / temperature the liquids and egg shells are kept. There may be other variables that your child suggests which might be worth considering.

Carry out the investigation and ask your child to record the data in a simple table. The focus should be on the quality of observations that can be made, rather than producing graphs, as we are not measuring numerical data in this investigation.

Ask your child to rank the drinks, based on the results, in order of how much damage they think each would do to our teeth. What conclusions can we draw? Anything as predicted or unexpected?

Assignment

Please ask your child to complete Assignment 3.

You may find it helpful to watch the following video before completing the assignment which will discuss how we evaluate investigations.

We would also encourage you to read the following document which provides a ‘model response’ to similar questions to those found at the end of the assignment.

📄 READ - Year 4 Science Investigation Writing

Citations

[1] www.youtube-nocookie.com