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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
 Thermometer Collection
 Liquid Crystal
 Absolute Zero
  video  - Thermal Expansion
 LN2 - Thermal Effects on Solids and Gases
 Heat And The First Law
 Change Of State
 Kinetic Theory
 Gas Law
 Entropy And The Second Law

LN2 - Thermal Effects on Solids and Gases


To give a qualitative look at thermal contraction by showing how various items shrink and change texture when drastically cooled.


Each item in turn is immersed in the liquid nitrogen and allowed to come to thermal equilibrium. The item is then removed and its new properties are investigated.
  • Rubber items become very brittle.
  • Metal objects shrink as do the balloons and rubber balls.
  • Bananas shatter while green leaves crumble to dust in your hands. After dipping banana in LN2 for 1-2 min, place on table or floor and use hammer to shatter it.
  • A penny can be easily broken (not bent) with a hammer in an anvil, or place pennies in a cup filled w/ LN2, then dump onto table and use hammer to shatter 1982 & newer pennies (made mostly of zinc w/ a copper coating), while older pennies don't really break (made mostly of copper).


  • Ball and ring device
  • Balloon
  • Food Items
  • Glass Dewar
  • Hammer
  • Liquid Nitrogen
  • 2 Rubber Ball
  • Rubber Knives
  • Rubber Tubing