This Kapow pupil video is part of the Kapow Science scheme of work. Solids have a fixed shape and volume, which means they can’t be compressed and don’t change shape unless a force is used. Unlike liquids, solids don’t flow or take the shape of their container – they stay the same.

But what about a sponge? When you squeeze it, it gets smaller. That’s because the sponge is full of tiny holes filled with air. The air gets squeezed out, but the solid parts of the sponge stay the same. And what about sand? It looks like it flows, but that’s because it’s made of lots of tiny solid grains. Each grain still has a fixed shape and volume. So remember: if something keeps its shape and can’t be squashed easily, it’s a solid.

The video is designed to be shown to pupils as part of Science, key stage 2, Year 4, Materials: States of matter, Lesson 1: Solids