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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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 Thermal Properties Of Matter
 Heat And The First Law
 Heat Capacity using Wax and metal Balls
  video  - Convection Box
 Convection Chimney
 Chimney with Vane
  video  - Heat Conduction
  video  - Thermal Conductivity
  video  - Light The Match
 Leslie Cube
 Boiling Water in a Paper Cup
 Steam Gun
  video  - Fire Syringe
 Jug O' Air
 Change Of State
 Kinetic Theory
 Gas Law
 Entropy And The Second Law

Jug O' Air


An illustration of adiabatic cooling.


A thermistor connected to a multimeter (LED bar) gives an indication of the temperature inside the jug measured in Fahrenheit (relative). Plug the jug with the rubber stopper and pump air into the jug. The increase in pressure is associated with a rise in temperature of the air in the jug. Keep pumping until the cork pops off the jug. The air in the jug will go through a period of rapid cooling as seen on the meter. The air will actually cool to a lower temperature than it started with.


When using the LED bar, make sure the polarity of the voltage signal going into the LED bar is positive (you may adjust the leads at the thermistor circuit). The following amplifier settings has worked in the past:

Keithley 427 Current Amplifier
  • Gain = 104 V/A
  • Suppression = 10-7 A
  • Rise Time = 0.03 ms
Check the voltage on both 9V and AA (1.5V) batteries in the thermistor circuit.