Phase Change
Properties of Matter

Festive Star

Enrichment Activity for 5-11 11-14

Missing media item.

What you need

  • Large glass of hot water

  • Pencil
  • Two pipe cleaners
  • Borax (available from most hardware shops)
  • Blue food colouring
  • Spoon

Instructions

  1. Cut one pipe cleaner in half. Twist the two halves around the second pip cleaner to make a six pointed star.
  2. Twist the long point around a pencil so the star can hang from it.
  3. Fill a class with enough hot water so that the star will be completely covered when it's hanging from the pencil.
  4. Add some colouring to the water.
  5. Stirring, add borax to the water until no more will dissolve. This will be about 4 or 5 spoonfuls.
  6. Hang the star in the water and wait overnight.

Results and Explanation

A sparkly star emerges.

The rough surface of the pipe cleaners act as a nucleation site, encouraging the borax molecules to come out of solution and form crystals. They grow overnight as more and more borax molecules attach to the crystal surfaces.

Phase Change
can be analysed using the quantity Energy
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