2. Temperature units and measurement

Units of Temperature:

There are three units commonly used to measure the temperature:

Celsius is written as \(°C\) and read as a degree. For example, \(100\)\(°C\) is read as hundred degree Celsius. Celsius is also called a Centigrade.

 

  

Fahrenheit is written as \(°F\). For example, \(100\)\(°F\) is read as hundred degree Fahrenheit.

 

  

Kelvin is written as K. For example, \(100\)\(K\) is read as hundred Kelvin. SI unit of temperature is Kelvin.

 

 

The temperature of the substance is the approximation of the average kinetic energy of the substance. Higher temperature means the molecules inside the substance are moving rapidly. Similarly, lower temperature means that the molecules are moving in a slow phase.

 
The movement of the molecules is directly proportional to the temperature. Since the molecules in any substance are very small to compute, it is really difficult to measure the movement of the molecules (Kinetic energy). So we need to look at indirect ways to measure this movement (Kinetic energy) of the molecules.

  

Solids, liquids and gases are affected by heat. When we heat, the substances start to expand, and they start to contract when we cool them. This principle is used to measure the temperature. The thermometer is used to measure the temperature.