National Chemistry Week - Experiments - Expansion on Freezing

THE AIM:

To show that water expands when it is frozen.

WHAT YOU WILL NEED:

• 1 clear film canister or other small, clear plastic container
• water
• freezer
• 1 rubber band

WHAT TO DO:

1. Fill the film canister with water until it is about 1/2 cm from the top.
2. Place the rubber band on the outside of the container at the top of the water level.
3. Place the film canister in the freezer.
4. When the water is frozen remove the film canister from the freezer.
5. Encourage observations.

When water freezes the distance between the water molecules gets a little larger and this causes the water to expand. Because frozen water has more space between its molecules than liquid water has, frozen water (ice) floats in liquid water. This is why ice cubes float.