Changing Materials

Duration 1h

Hear dry ice ‘scream’, see crispy rice burnt with a blow torch and explore the weirdness of slime in this exploration of the different states of matter. Cheese making and launching effervescent rockets add to the fun.





Key Words

States of matter. Solids. Liquids. Gases. Heating and cooling. Reactions. Reversible and irreversible.

Learning objectives

  • Recognise that most materials can be separated into solid, liquid and gas.
  • Understand that materials change when mixed, heated, or cooled.
  • Gain an appreciation that some changes are reversible, while some are irreversible.
  • Recognise melting and freezing are reversible changes.
  • Recognise burning as a non-reversible change that results in the formation of new materials.


Students will:

  • See a non-Newtonian materials (slime).
  • Enjoy demonstrations using dry ice and rice crispies.
  • Watch the incineration of a rice crispy.
  • Learn about the preparation of (and take away to eat!) chocolate rice crispy cakes.
  • Launch some pop-rockets.
  • Experiment with cheese making.

Curriculum Links

Year 4

States of Matter

  • Compare and group materials together, according to whether they are solids, liquids or gases.
  • Observe that some materials change state when they are heated or cooled.

Year 5

Properties and changes of materials

  • Compare and group together everyday materials on the basis of their properties.
  • Demonstrate that dissolving, mixing and changes of state are reversible changes.
  • Explain that some changes result in the formation of new materials, and that this kind of change is not usually reversible, including changes associated with burning.
  • Use knowledge of solids, liquids and gases to decide how mixtures might be separated, including through filtering, sieving and evaporating.

Potential Hazards

Observation of dry ice demo; handling milk, lemon juice and vitamin C tablets; eating chocolate, marshmallow and crispy snack.




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