States of Matter in Action

All the material around us is made of matter. Matter exists in three main states: solid, liquid, and gas. The state of matter depends on how the tiny particles (atoms and molecules) inside it are arranged and how much they move.

Solid

• Has a fixed shape and a fixed volume.
• Particles are packed tightly together and vibrate in place.
• Examples: ice, rock, wood, metal spoon, glass.
• Solids keep their shape unless a force is applied to them.

Liquid

• Has no fixed shape — takes the shape of its container.
• Has a fixed volume — the amount stays the same.
• Particles are close together but can slide past each other.
• Examples: water, juice, cooking oil, melted wax, blood.

Gas

• Has no fixed shape and no fixed volume — fills any container.
• Particles are far apart and move quickly in all directions.
• Examples: air, steam, carbon dioxide, helium in a balloon.
• Gases can be compressed (squashed into a smaller space).

Changing States

• Melting — a solid heated enough becomes a liquid (e.g., ice melts into water at 0°C (32°F)).
• Freezing — a liquid cooled enough becomes a solid (e.g., water freezes into ice).
• Evaporation — a liquid heated enough becomes a gas (e.g., water becomes steam).
• Condensation — a gas cooled enough becomes a liquid (e.g., steam cools into water droplets).