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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
 Change Of State
 Ice Bomb (expansion of water upon freezing)
 Regelation in Ice
  video  - Thermocouple in Ice
  video  - Boiling by Cooling
  video  - Boiling by Reducing Pressure
  video  - Crush the Soda Can
 Sling Psychrometer (Relative Humidity)
 Phase Change in Iron
 Kinetic Theory
 Gas Law
 Entropy And The Second Law

Regelation in Ice


Substances that expand on freezing show a lower melting point under pressure. Regelation is the phenomenon of melting under pressure and freezing again when the pressure is reduced. This can be demonstrated by cutting through a block of ice with a wire loop that has a heavy mass hanging from it.


This demo must be requested well in advance, so that we can freeze a block of ice overnight. Cut the top off of a 12 oz (or longer) soda can. Fill with distilled water and place in staff lunch room freezer overnight. Slow cooling just below water's freezing point makes clearer ice. Just before showing demo, remove ice block, place piano wire over it hanging heavy weights on the ends. This can be done many different ways, with or without pulleys. An example of regelation includes the flow of glaciers.