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Year 2 Science Physical Sciences

States of Matter

Everything around us is matter. Matter exists in three main states: solid, liquid, and gas.

🪨

Solid

Fixed shape. Particles packed tightly. Cannot be compressed.

Examples: rock, ice, wood, metal

💧

Liquid

Takes shape of container. Particles less tightly packed. Flows.

Examples: water, juice, milk, honey

💨

Gas

No fixed shape or volume. Particles spread out. Fills any container.

Examples: air, steam, oxygen, helium

Changing states

Matter can change from one state to another when heated or cooled:

  • Ice (solid) + heat = Water (liquid)
  • Water (liquid) + heat = Steam (gas)
  • Steam (gas) + cooling = Water (liquid)
  • Water (liquid) + cooling = Ice (solid)

Special names

  • Melting: solid → liquid (ice melts)
  • Freezing: liquid → solid (water freezes)
  • Evaporation: liquid → gas (puddles dry up)
  • Condensation: gas → liquid (steam on mirror)

Water in nature

Water is special — it naturally exists as all three states on Earth: solid (icebergs), liquid (rivers and oceans), and gas (water vapour in the air). The water cycle moves water between all three states.

Properties of each state

  • Solids: keep their shape, hard or rigid
  • Liquids: flow, take the shape of container
  • Gases: fill all available space, invisible

Key Vocabulary

matter — anything that takes up space and has mass
solid — matter with a fixed shape and volume
liquid — matter with a fixed volume but no fixed shape
gas — matter with no fixed shape or volume; spreads to fill space

Knowledge Check

Question 1

Which of the following is a solid?

Question 2

When ice is heated and melts, it changes from a solid into a:

Question 3

Why do gases fill the entire container they are put into?

Question 4

When water vapour (steam) touches a cold surface and turns back into liquid water, this process is called:

Lesson Summary