Phase Changes: Liquid-Gas: Air Balloon in Liquid Nitrogen

PIRA Class: 4C30.32

Purpose: 

To observe the gas-to-liquid phase change of air.

Description:
Produce Liquid Air in the bottom of a test tube.

Use eye and hand protection!

1. Order liquid nitrogen (LN2) the day prior to the demonstration.

2. Inflate a medium sized balloon and secure opening over the top of a test tube.

3. Pour LN2 into glass beaker. When the boiling has "relaxed" a bit (i.e. beaker comes into thermal equilibrium with contents) - add more LN2 to fill beaker to the top.

4. Place test tube (w/ balloon on top) into LN2 and wait ~ minutes.

5. Remove test tube when balloon is significantly deflated.

6. Have students immediately observe the cloudy liquid (air) within the test tube. Test tube will quickly fog/ frost up - so be quick with the show and tell. As test tube and contents warm up to room temperature, balloon will re inflate.

Equipment:
Balloon, Test Tube, Liquid Nitrogen, large beaker, goggles, gloves

Web Simulation:

TBD

Location:
Shelf 164 (balloon), 262 (beaker), 264 (gloves), liquid nitrogen near the sink