Heat Class 7 Science - Hot and Cold

Heat Class 7 Science - Hot and Cold
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Things around us could be hot or cold. The hotness or coldness can be identified by touching the object. The measure of hotness or coldness of an object is called its temperature. Temperature is measured by a device called thermometer. A common thermometer is one of the device to measure the temperature. In general it is the liquid-in-glass thermometer. Mercury and alcohol are the liquids used in most of the liquid-in-glass type thermometers. These thermometers work on the principle that the volume of the liquid varies based on temperature.