Product Instructions: Bursting Bottle
HE82325 & HE82327
These cast iron bottles are designed to demonstrate the expansion of water as it freezes.
They are intended as a single-use item, as the demonstration results in breakage of the bottle.
The bottles are made entirely of cast iron, and are open at one end. The end is threaded to
accept a bolt.
They are available with or without a plug.
Bottle and plug HE82325
Bottle without plug HE82327
www.timstar.co.uk [email protected]
01270 250459 01270 250601
Product Instructions: Bursting Bottle
Requirements
• Freezing mixture of salt and ice
• Bucket
• Piece of cloth
• Water
Boiling the water before the demonstration ensures there is no air in it. Air is easy to compress,
so if there is any air in the bottle, the ice will expand into this instead of breaking the bottle.
Cool the bottle before the experiment to reduce the amount of time for the water to freeze.
Demonstration
1. Fill the bottle with water.
2. Remove the air bubbles by tapping the bottle gently.
3. Ensure the bottle is completely full of water, and screw the lid on tightly.
4. Bury the bottle in the ice/salt mixture, and cover with a cloth.
Eventually the iron bottle will break as the ice expands, and the breakage can be clearly heard.
Theory
You may wish to first demonstrate the ball and ring experiment, to show that most materials
contract as they cool. Challenge students to explain why water expands as it freezes.
The answer is that ice has a crystal structure, where the water molecules move into a welldefined position, compared to water where the molecules are free to move. In water, typical
molecules are closer together than in ice, so they occupy less space.
Safety
After placing the bursting bottle in the ice/salt mixture, place a cloth over the bucket, so when
the bottle bursts, no debris is ejected.
A full risk assessment should be carried out before hand, in accordance with school policy.
www.timstar.co.uk [email protected]
01270 250459 01270 250601