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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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 Electric Fields And Potential
 Current and Resistance
  video  - Resistance Model
  video  - Temperature Effects on the Resistance of Copper Wire
 Temperature Effects on Resistivity
  video  - Superconducting Wire
 Electromotive Force And Current
 DC Circuits
 Magnetic Materials
 Complex Circuits
 Semiconductors And Tubes
 Transmission Lines and Antennas

Temperature Effects on Resistivity


To demonstrate the effects of low temperature on the resistance of copper, niobium, and carbon resistors.


Measure the resistance of each element at room temperature, then immerse the probe in the liquid nitrogen. With the meter connected, the change in resistance can be observed.


Remember if resistivity is parametrized as
carbon has negative a and the resistance increases with lowering of the temperature. Niobium shows very mild decrease of the resistance compared to the copper.


  • Digital Multimeter
  • Connecting Wires
  • Liquid Nitrogen
  • Resistance probe