Phase Change
Properties of Matter


Enrichment Activity for 5-11 11-14

What you need

  • Bottled or distilled water (not tap water)
  • Freezer


  1. Put the bottle of water in to the freezer
  2. Leave it alone for two to three hours. You’ll need to experiment with the exact timing as all freezers are different
  3. Check regularly that the water is still liquid – but don’t move the bottle! While the water is still liquid, take the bottle out of the freezer carefully, then tap it suddenly on the edge of a table

Results and Explanation

The water will freeze! Water can stay liquid for several degrees below 0°C if there are no impurities or disturbances to start ice crystals forming. Tapping the bottle disturbs the ‘supercooled’ water and kicks off freezing.

Phase Change
can be analysed using the quantity Energy
IOP DOMAINS Physics CPD programme

Electricity CPD videos

Our new set of videos gives teachers and coaches of physics a preview of the training we offer ahead of this term's live support sessions.

Find out more