2B30.30-Magdeburg Hemispheres


Video: Watch this demo

Instructor’s video

Description: This demonstration shows a behavior of atmospheric pressure.


  • Vacuum pump
  • Magdeburg Hemispheres

Setup Procedure:

  1. Plug the vacuum pump in and make sure it works.

Demonstration Procedure:

  1. Have a small student pull apart the hemispheres with the vacuum pump off (easy).
  2. Now, turn on the vacuum pump and have a strong student try and pull them apart (very hard).
  3. When finished, turn off the vacuum pump.


To open these, the student would have to pull with a force of about 250 pounds. (Optional) To do this out, say the radius of each disk is 1.6in. The surface area (pi*r*r) is thus about 16 square inches for both spheres. The atmosphere has on about 14.7 PSI, so that comes out to about 280 pounds of force.


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