Water Expands When it Freezes

Equipment Needed

Water
1 Plastic cup
A freezer

The Experiment

Fill the cup up to the brim with water.

Place the cup in the freezer and wait for all of the water to freeze.

The ice will come up much higher than the brim of the cup.

Alternate Experiment

The following experiment requires the outside temperature to remain below the freezing temperature of water overnight, so whether you can perform the experiment will depend on where you live.

Equipment Needed

Water
1 glass bottle with a very strong lid

The Experiment

Fill the bottle to the top with water, and then close the lid tightly.

Place the filled bottle outdoors and leave it overnight.

In the morning, the water in the bottle will have frozen and turned to ice.

The sides of the bottle will be cracked open. (Be careful of broken glass.)

How it Works

The ice requires more space than the water that was originally poured into the bottle. It cannot expand upward because the lid is stopping it, so it expands sideways instead, cracking the glass.