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Electricity from heattrdeating coils convert electricity into heat. This--i an example of an energy transformation; o.re:orm_ of energy (electricity) is converted intoinother form (heat). The opposite process, heat:,rnverted to electricity, can be accomptished byz thetmocouple.A thermocouple consists of two wires of differ

ent metals joined at two places so that they^'orm a loop. If the two places where the wires;oin (the junctions) are at different tempera-:ures, a small electric current flows along ther-ire. If one junction of the thermocouple isplaced in a glass of iced water and the other isplaced in a candle flame, the current is toosmall to light a bulb, but it can be detectedrsing a sensitive current-detecting meter (anammeter). Thermocouples are used as ther-nometers in refrigerators, househoid hot-water-.1-stems, and in many industrial processes.

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Electricity is used to heat an electric steelfurnace. ln an electric arc lulnace, a spark(or arc) jumps between an electrode andthe metal. This melts the metal so that itcan be run ofl through a hole at thebottom.

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You will need a 4.5 volt battery andtwo pieces of wire with bare ends.Connect a piece of wire to eachterminal of the battery. Now slowlypress together the ends of thewires using your barefingers. You will soonfeel the wires heatup at the pointwhere they aretouching. Pull thewires apart as soonas you feel theheating, otherwise the batterywill quickly run down. Also, NEVERuse a high-powered battery for thisexperiment or you could burn yourfingers.

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