demonstrations:liquid_nitrogen_freezing_bouncy_ball
Freezing a Bouncy Ball in Liquid Nitrogen
Materials: ★★★ Requires materials not commonly found in school laboratories
Difficulty: ★★☆ Can be done by science teachers
Safety: ★★★ Only to be attempted with adequate safety procedures and trained staff
Categories: Materials, Liquid Nitrogen
Alternative titles: Unbouncy Ball Experiment
Summary
A bouncy ball submerged in liquid nitrogen loses its elasticity because the extreme cold freezes its rubber molecules into a rigid, brittle structure. As a result, the ball cannot compress and rebound, making it unable to bounce until it warms up again.
Procedure
- Place a bouncy ball into a container of liquid nitrogen using tongs.
- Leave the ball submerged for several minutes until thoroughly cooled.
- Wearing safety glasses and gloves, remove the frozen ball.
- Drop the ball onto a hard surface and observe its reduced bounce (or shattering).
- Allow the ball to return to room temperature and test again to see its bounciness restored.
Links
Can you FREEZE a bouncy ball? | liquid nitrogen experiment - Wonderlab+:
Don't Put Bouncy Ball in Liquid Nitrogen - Mr. Ax: The BackBencher Experiment:
Variations
- Compare different types of balls (rubber superballs, tennis balls, racquetballs).
- Drop the frozen ball from different heights to see if it shatters or simply thuds.
- Test the bounce height of the ball at room temperature versus after freezing.
- Use slow-motion video to capture the difference in impact behavior.
Safety Precautions
- Safety glasses required.
- Wear cryogenic gloves when handling liquid nitrogen and the frozen ball.
- Handle the ball with tongs immediately after freezing — it may be brittle and sharp if it breaks.
- Only perform in a well-ventilated area to prevent nitrogen buildup.
- Do not attempt this with balls containing liquids or pressurized gas (they may burst).
Questions to Consider
- Why does rubber normally allow a ball to bounce?
- How does liquid nitrogen change the molecular structure of rubber?
- Why does the frozen ball sometimes shatter like glass?
- What type of energy conversion allows a normal ball to bounce?
- How does warming the ball restore its elasticity?
- What other everyday materials might behave similarly when frozen with liquid nitrogen?