Temperature dependence of resistance.
A light bulb is placed in series with a coil and a storage battery. The coil is at the end of a rod which may be lowered into a dewar of liquid nitrogen. The light burns much more brightly when it is cooled because its resistance is decreased.
|Coil fixed on one end of a rod||021-11C|
|Liquid nitrogen and dewar||017-21A|
|DC power supply|