Everything around you is made up of tiny particles. Each individual particle is far too small to see. In some materials the particles are very tightly packed together and can't move around, so the material keeps its shape. Materials like this are called solids.
In other materials the particles are not so tightly packed and are able to move around each other. This means that the material can change shape to fit whatever container it is put in. Materials like this are called liquids. It is possible for solids to change into liquids and for liquids to change back into solids.
In this worksheet you can try to answer some questions about solids and liquids and test what you know about these two forms of matter.