Experiment 1
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Take half kg of water in a vessel. Note its temperature
Heat it for exactly 2 minutes using a Bunsen burner. Again note down its temperature
Experiment 2
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Rise in temperature in the 2nd experiment is half that in the 1st experiment.
Inference - Rise in temperature of a substance due to same amount of heat depends on the amount of substance taken.
Experiment 3
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Now, repeat the whole experiment with castor oil (half kg) in the same vessel. Let its initial temperature be
Again heat it exactly for two minutes (so that same amount of heat is supplied to castor oil). Note its temperature as
The experiment may be repeated with different liquids (or solid pieces). Each time we find that rise in temperature after two minutes in each case is different.
Inference
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When same amount of heat is supplied to different substances of equal mass at the same initial temperature, rise in temperature for different substances is different.
We can say, different substances of equal mass require different quantity of heat to increase their temperature by one degree Celsius. This is a characteristic property of a given substance and is known as 'Thermal Capacity'.
Thermal capacity is defined as
“the quantity of heat required to increase the temperature of the substance through one degree Celsius”.
