4E20.40-Balloon in Vacuum

4e2040 4e2040b

Video: Watch this demo

Instructor’s video

Description: This demonstration shows what happens to the volume of a balloon when pressure is reduced.


  • Vacuum pump
  • Bell jar
  • Balloon

Setup Procedure:

  1. Inflate the balloon only a little as shown in the first picture. Place in the bell jar.
  2. Connect the bell jar to the vacuum pump. Leave the valve open.
  3. Plug in the vacuum pump.

Demonstration Procedure:

  1. Note to the students the size of the balloon.
  2. Turn on the vacuum pump.
  3. Note that the balloon inflates due to the decreased pressure inside the bell jar.
  4. When finished, turn off the vacuum pump.