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Al Tobias (wat4y) - Office: Gibson S123 & Physics 218, (434) 924-0538

Physics Demo Manual

Demonstrations are cataloged according to PIRA Bibliography


Due to Physics Building renovations, the lead time to set up demo requests has increased due to the need to transport equipment across campus. Please be kind and let me know well ahead of time what you need.

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 Surface Tension
 Fluid Statics
 Hydrostatic Pressure dependence on depth
  video  - Pascal's Vases
 Hydraulic Press
  video  - Balloon in Vacuum
 Marshmallow Man
  video  - Crush the Soda Can
 Magdeburg Hemispheres
 Pressure Gauges
 Qualitative Pressure Gauge
  video  - Archimedes' Principle I
 Archimedes' Principle II
 Archimedes Principle III
 Cartesian Diver
 Buoyancy of Air
  video  - Weight of Air
 Fluid Dynamics

Archimedes Principle III


To demonstrate the buoyancy of lighter gases in the air.


A variety of experiments can be shown.
1. A trash bag can be inflated with hot air using a heat gun blowing into an upright standing pipe. The trash bag will float to the ceiling.
2. A helium filled balloon can be released in to a vertically positioned tall fish tank. The balloon will float. Once the tank is filled with helium as well the balloon dives down.
3. Fill the soap film with methane gas. The bubbles will float in the air. For a theatrical effect the demonstrator can pop the bubble with a lighted candle on a long stick which will produce very SFX like flames.


1. Careful with the edges of the blower pipe it gets hot and easily melts the bag.