Photo Shows the Apparatus Used at U.T. Austin

• The baroscope is initially balanced under atmospheric pressure.


• Place the glass hood on top of the baroscope and turn on the vacuum.


• Observe the styrofoam ball drop.


• Faculty may also release the vacuum seal and observe the baroscope rebalancing.

Concepts Conveyed:

• Demo consists of a suspended styrofoam ball and an adjustable counter weight.


• Demonstrates the buoyancy forces on a body due to changes in atmospheric pressure.


• The loss of weight of an object in air equals the weight of the air displaced by it.

Demo Staff Notes:

• Balance the rod with the styrofoam ball horizontally using the counter balance.


• Place the baroscope on the vacuum chamber plate without the glass hood.


• Verify that the baroscope is still balanced once rolled into the classroom.