Changing shape

Squash it, roll it, shape it!

Push and pull to change shape

A force is a push or a pull. Forces can change the shape of some materials.

A bigger push or pull can make a bigger change of shape.

Squash a ball of dough and it goes flat. Squeeze a sponge and it gets smaller.

Kneading makes dough soft and stretchy so it is easy to roll.

To make roti, you roll the dough with a rolling pin. The push makes a flat circle. Potters push and shape soft clay into pots.

Once roti is cooked, it keeps its new shape.

Try to squash a stone or a spoon. They do not change shape. Some materials are too hard to squash with your hands.

Rocks do change shape, but only very slowly, over many years.