Solids

Solid things hardly ever changes their shape or size. You can test this for yourself. Put two solid things, a piece of wood and a pebble, on a table. Measure them and remember what shape they are. Look at them again a few days later. Have they changed their size or shape? Will they change unless you cut them or smash them? This is one way in which solid things are different form liquids and gases.

Most of the things we find around us are solids. One solid you are sure to have in your home is sugar. If you look at sugar closely with a magnifying glass, you will see it is made up of thousands of tiny colourless pieces. These are the crystals of sugar.

Many other solid things make crystals, too. You can see shiny crystals in different colours and in different shapes. Some minerals make crystals shaped like tiny blocks. Others make long pointed crystals, rather like sharpened pencils.

In most rocks, the different shaped crystals are pressed tightly together. In some rocks, there are holes and here the crysals have space to grow into the most beautiful shapes.

Ice can also make beautiful crystals. You may see them on your window o a frosty morning, making feathery patterns as they may grow along the glass.