We need to get energy into our bodies so that we can continue to live. We also need materials to make up our tissues. To do that we need to process other things. These other things we call food.

Eating is all about changing food from hard or large shapes into soft and small ones so that the rest of the body can make best use of them.

The front teeth are sharp so they can bite off bits of food. The back teeth are broad and flatter so they can crush the bits after they have been bitten off. The tongue transfers material from the front to the back of the mouth. This happens without you realising it, but if you take notice of how your mouth works, you will feel it happening.

When food is crushed, its surface area gets greater. This is important, because inside you is a chemistry set and all chemical actions take place on the surfaces of things, so the bigger the surface, the faster the action will be.

The mouth also releases saliva, a complicated substance that is an acid and which also contains many other materials designed to speed up the dissolving of food.

All of this then gets pushed into your throat by the muscles in the back of your tongue, swallowed and sent to the stomach for more processing.