Physics Demo Manual

Demonstrations are cataloged according to PIRA Bibliography

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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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Temperature Effects on Resistivity

Purpose:

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

Procedure:

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.

Hints:

Remember if resistivity is parametrized as
rho2=rho1(1+a*dT)
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.

Equipment:

Digital Multimeter
Connecting Wires
Liquid Nitrogen
Resistance probe