4E10.20 Balloons in liquid nitrogen
Thermal expansion/contraction, gas law at constant pressure
An air-filled balloon cooled in liquid nitrogen will shrink. When warmed back up in air, the balloon re-inflates.
Skilled individuals can make balloon animals to dunk in liquid nitrogen. Otherwise, just dunk the balloon "snake."
-  1 L Dewar with liquid nitrogen
-  Balloon
-  Twisting balloon
-  Balloon pump
-  Safety glasses
-  Safety gloves
- Place the Dewar on the lecturn shelf.
- Inflate a balloon. If using the twisting balloon, leave a 2-inch unfilled section on the end.
- Liquid nitrogen can cause severe burns and blindness. Use with caution.
- The balloons can pop prematurely. Bring extras.
- Pump air into the balloon until there is only a 2-inch unfilled section on the end.
- Make a balloon animal (dog suggested). Give it a name.
- Put on your safety glasses and gloves.
- Put the balloon (mention by name) into the dewar of liquid nitrogen. Use forceps to completely immerse the balloon. Make sounds of dismay as the balloon shrivels up.
- Pull the balloon out of the liquid nitrogen and perform "CPR" by blowing on it with your warm breath. The balloon should be mostly back in proper form.
- PIRA 4E10.20
- Don't attempt this at home!
- Qualatex balloons work well for balloon animals.
If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.