Temperature

Temperature is a measure of the degree of hotness or the intensity of sensible heat. Whenever two bodies at different temperatures are brought into thermal contact, heat flows from one at a higher temperature to the other at a lower temperature.

Temperature may be defined as the thermal condition of a body that determines the direction of heat flow i.e. it determines whether the body will receive heat from another body or it will give heat to the same. 

The human body is quite sensitive to changes in temperature. But the sense of touch is purely qualitative. while scientific experiment requires that every physical quantity should be measurable. Instruments which is used to measurement of temperature are called thermometers.

SI Unit of Temperature

The SI unit of temperature is Kelvin (K). Other units of temperature are °C and °F and the three temperature scales are the Fahrenheit scale, Celsius scale, and Kelvin scale.

Measurements of Temperature

Because molecules are such tiny particles, we must use an indirect method to estimate their kinetic energy. When a substance is heated, the molecules within it move more quickly. The increased mobility caused most material volume or space to slightly increase (motion). The expansion of a material is used by thermometers as a proxy for temperature measurement.

Heat and Temperature are two related terms that people may confuse often. It should be noted that Heat and temperature are two different quantities. The fundamental difference between heat and temperature is that Heat is the form of energy that transfers from a hot state to a cold state. The unit of Heat is Joule. However, the temperature is the measure of the hotness and coldness of an object. The SI unit of Temperature is Kelvin. 

As shown below, water is boiling on a gas burner in a utensil. It can be observed that heat energy is transferred from the gas burner to the water when boiled. The water gets boiled at 100 °C, which is its temperature, and is measured with the help of a thermometer.