According to heat definition, it is one of the essential forms of energy for the survival of life on earth. Transfer of heat takes place from one body to another due to differences in temperature as per thermodynamics. We use heat energy for various activities like cooking, ironing, transportation, recreation, etc. This form of energy also plays a vital role in nature. The occurrence of the wind, rain, change of seasons, etc., depends on the gradient created due to uneven heating of different regions. In this article, let us learn what is heat and its classification.
What Is Heat?
With the increase in a body’s temperature, molecules or atoms’ vibrations increase. These vibrations are then transferred from one part of the body to another. The measure of energy with which the molecules vibrate in a system is termed as heat stored in that object.
As per the definition of heat, it is defined as the flow of energy from a warm to a cooler object. The direction of flow of the heat energy takes from the substance of higher temperature to the substance of lower temperature. This is because the molecules are vibrating faster and transfer their energy to the molecules vibrating slower. The vibrational energy is also termed as its heat content. The heat content in the body makes it hot or cold. Greater the heat content, the hotter the body will be.
A substance may absorb heat without an increase in temperature by changing from one physical state to another. In the process of melting, the substance is changed from solid to liquid. In the sublimation process, the solid is converted into a vapour state. In the process of boiling, the liquid is converted to vapour. Heat is a form of energy that can be converted into work. The amount of energy is expressed in units of work. It is expressed in joules, foot-pounds, kilowatt-hours, or calories.
Heat as a form of energy can be converted to other forms of energy. For example, in motorized vehicles, heat is converted to mechanical energy. In electric bulbs, it is converted to light energy. In thermal power plants, it is finally converted to electrical energy.
Let us take three beakers, first with cold water, the second with hot and the third with water at normal temperature. If we dip our fingers in beaker 1 and then in beaker 3, we will observe that the water in beaker 3 is hot compared to that in beaker 1. Whereas, if we dip our fingers in beaker 2 and then in beaker 3, we will observe that the water in beaker 3 is colder as compared to that in beaker 2. This shows that we cannot rely on our sense of touch to judge the hotness or coldness of something, and that’s why the degree of hotness or coldness of any object is measured in terms of temperature.
Temperature is the measure of hotness or coldness of the body. Celsius (C) or Fahrenheit (F) scale, or in Kelvins (K). Relations are established on the amount of heat added to taken out from the body.
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