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What is matter?

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Quick answer

Matter is anything that has mass and takes up space — everything you can touch, from air and water to rocks and stars. All ordinary matter is made of atoms, and it exists in states like solid, liquid, gas, and plasma.

Key things to understand

  1. Matter has two defining properties: it has mass and it occupies volume (space).
  2. It's made of atoms, which combine into molecules and larger structures.
  3. Its common states — solid, liquid, gas, and plasma — depend on how much energy its particles have.
  4. Matter can change state (ice melting to water) without becoming a different substance.
  5. Not everything is ordinary matter — light is energy, and 'dark matter' is a mysterious, invisible form inferred from gravity.

People also ask

What are the states of matter?
The four common states are solid, liquid, gas, and plasma. Which one a substance is in depends on temperature and pressure.
Is light matter?
No. Light is a form of energy carried by particles called photons, which have no mass — so light isn't matter in the ordinary sense.
What is matter made of?
All ordinary matter is made of atoms, which are themselves built from protons, neutrons, and electrons.