PURPOSE: To determine the equivalence between electrical energy and heat energy (the electrical equivalent of heat).

DESCRIPTION: An immersion heater is placed in a water bath and operated for a measured amount of time. Its voltage and current are measured and displayed by meters on the overhead projector. From this the electrical energy input into the calorimeter can be determined. The temperature of the water bath and calorimeter can be measured before and after the heat is added, and the heat energy increase in the calorimeter determined. The two results can be compared to determine the electrical equivalent of heat.


REFERENCES: (PIRA 5F15.10) See Demonstration Reference File for other necessary data and results of a sample experiment.

EQUIPMENT: Electric calorimeter, overhead projector voltmeter (0-20 VAC) and ammeter (0-2AAC), digital thermometer, timer, beaker with about 150 g water.

SETUP TIME: 10 min.

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