Temperature and its Measurement

Class 06 Science

Some bodies are hotter than others. For example, during summers, the tap water may be hotter than the cold water from a matka (earthen pot) or a refrigerator. You can realise this by merely touching the two samples of water.

Temperature

A reliable measure of hotness (or coldness) of a body is its temperature. A hotter body has a higher temperature than a colder body. The difference in temperature between the two bodies tells how hot a body is in comparison to another body. A device that measures temperature is called a thermometer.

There are two kinds of thermometers - clinical thermometers and laboratory thermometers. Clinical thermometers are used to measure human body temperatures whereas laboratory thermometers are used for many other purposes.

For measuring temperature, the clinical thermometers generally use a scale called the Celsius scale. On this scale, the unit of temperature is degree Celsius and is denoted by °C.

The normal temperature of a healthy human body is taken to be 37.0 °C. The temperature of human beings does not normally go below 35 °C or above 42 °C.

There is another scale of temperature known as Fahrenheit scale. On this scale, the unit of temperature is degree Fahrenheit and is denoted by °F. A temperature measured as 37.0 °C on Celsius scale is equivalent to 98.6 °F on Fahrenheit scale.

In scientific work, there is another scale of temperature known as Kelvin scale. On this scale, the unit for temperature is kelvin and is denoted by K. The SI unit of temperature is kelvin.