Demonstrates resistance of a metal varying with temperature

To show that the resistance of a metal decreases when cooled; this demonstrates a positive temperature coefficient of resistance.

Dewar flask, liquid nitrogen, light and series wound resistor

1. Switch on apparatus and since the resistor is in series with the lamp and the 115 V supply for the lamp will not glow at full brightness. 2. Dip resistor into the liquid nitrogen and the light will shine brighter. Updated on: 01/18/16