Your chair, a glass of juice and the air you breathe have something in common: they are all matter.
Key idea
Matter is anything that has mass and takes up space. All matter is made of tiny pieces called particles, far too small to see.
Is air matter? Blow up a balloon: the air pushes the balloon outward, so the air takes up space. A pumped-up ball weighs a little more than the same ball when it is flat, so air has mass too.
Why it works
We cannot see air because its particles are spread far apart and are clear. We can feel it as wind, and we see it push a sail or fill a balloon.
Worked example: Matter or not?
Which of these are matter: a rock, milk, the steam over a hot bath, a shadow, a song?
- A rock, milk and steam have mass and take up space.
- A shadow is only where light is blocked; a song is sound, a kind of energy.
Answer: Rock, milk and steam are matter. A shadow and a song are not.
Common mistake
Thinking air is "nothing". Push an upside-down cup straight down into a bowl of water: the air inside keeps most of the water out.
Try it at home
- Stuff a dry paper towel into the bottom of a clear cup.
- Turn the cup upside down and push it straight down into a bowl of water. Hold it there, then lift it straight up.
- Is the towel dry? The air in the cup took up space, so the water could not get in.