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Science

Solid, Liquid, or Gas?

Overview

Children sort everyday materials into the three states of matter and discover that the same substance can exist in more than one state.

Learning Objective
Children classify materials as solid, liquid, or gas and describe the properties of each state.

Resources needed

  • Water
  • Ice or very cold water
  • A stone
  • A piece of cloth
  • A balloon

Lesson stages

0 / 7 done
  1. 1 Hold up a stone and water — ask: how are these different?
  2. 2 Introduce: scientists sort all materials into three states: solid, liquid, and gas.
  3. 3 Solid: has its own shape, hard to compress. Give examples.
  4. 4 Liquid: takes the shape of its container, flows. Pour water between containers to show.
  5. 5 Gas: fills any space, cannot be easily seen. The balloon contains air.
  6. 6 Sort a collection of materials: stone, water, ice, steam (described), air.
  7. 7 Ask: is water always a liquid? What happens when it is heated? Cooled?

Tap a step to mark it as done.

Variations

  • Heat water to show steam if possible.
  • Melt ice or butter to show solid turning to liquid.
  • Discuss cornflour mixed with water — is it solid or liquid?
More information

Teach: solid, liquid, gas, state, compress, flow, shape, container. Water in three states — ice, water, steam — is the single most effective illustration of all three states of matter.

Focus on solid and liquid only before introducing gas, which is the hardest state for children to conceptualise.

Can children correctly classify five materials as solid, liquid, or gas? Can they describe one key property of each state?

Water, ice or cold water, and air in a bag demonstrate all three states. No other equipment needed.

Children often classify materials by feel — sand seems liquid because it pours. Sand is a solid — each grain has its own shape. It is the collection that pours, not any individual grain.

States of matter underpin chemistry and physics. The idea that the same substance exists in different states depending on temperature introduces the concept of phase transitions.

Activity details
Primary Medium 20 minutes 5 minutes prep Whole Class, Small Group Indoor & Outdoor
Topics
States Of Matter Solids Liquids