You will need: a collection of materials like: foam plastic - wood modelling clay - soap chocolate - butter - chalk

Which materials do you think will change shape when they are squashed?
Draw the materials before you squash them.
Press each one with your finger.
Talk to your friends. How does the shape change? Does the material keep its new shape when you take your finger away?
Draw each material after you have squashed it.

We use materials which squash and stretch to make us comfortable.

Other materials do not change shape so easily. We use these materials to make things which must be strong.