Demos: 5B-10 Change of Resistance With Temperature
Change of Resistance with Temperature
A length of copper wire wound on a cylindrical form is in series with a battery, a switch and a small bulb. When the copper wire is at room temperature the bulb glows dimly when the circuit is closed. If now the copper wire is dipped in liquid nitrogen (contained in a small thermos bottle), its resistance goes down and the bulb glows brightly.