Grade 4 · Unit 3: Solids, liquids and gases

Matter

Everything around you is matter – even the air.

What is matter?

Matter is anything that takes up space and has mass. Your desk, your water bottle and the air you breathe are all matter. There are three main states of matter: solid, liquid and gas.

There is matter in places you might not expect: inside a balloon, in the steam from a kettle, and in the air in a football.

Solids

Solids keep their own shape. They do not flow. You can hold a solid in your hand. Wood, stone, ice and metal are solids.

Some solids, like sand and sugar, can be poured. But each tiny grain is still a solid with its own shape.

Liquids

Liquids flow and can be poured. A liquid takes the shape of its container, but its volume stays the same. Water, milk, oil and honey are liquids.

Pour 250 ml of water into a tall glass, then into a wide bowl. The shape changes, but there is still 250 ml – a liquid keeps its volume.

Gases

Gases spread out to fill all the space they are in. Most gases are invisible, but we can feel air as wind. Air, steam and the gas in a gas cooker are all gases.

Gases can be squashed into small containers. The cooking gas in a cylinder is squashed so much that some of it becomes a liquid.

What I learnt

• I know that matter is anything that takes up space and has mass.
• I can describe solids, liquids and gases.