HEAT

                              HEAT

INTRODUCTION:

              All substances in our surrounding are made up of molecules. These molecules are generally at motion and posses kinetic energy. At the same time each molecule exerts a force of attraction on other molecules and so they posses potential energy. The sum of the kinetic

and potential energy is called the internal

energy of the molecules. This internal energy, when flows out, is called heat energy. This energy is more in hot  substances and less in cold substances and flows from hot substances to cold substances.

DEFINITION:

                    Heat, energy that is transferred from one body to another as the result of a difference in temperature. If two bodies at different temperatures are brought together, energy is transferred—i.e., heat flows—from the hotter body to the colder.

TRANSFER OF HEAT:

                 Heat does not stay where we put it. Hot things get colder and cold things get hotter. Heat is transferred from one place to another till their temperatures become equal. Heat transfer takes place when heat energy flows from an object with higher temperature to an object with lower temperature. 

Heat transfer takes place in three ways:

          1.Conduction

          2.Convection

          3.Radiation

1.CONDUCTION:

                       The process of transfer of heat in solids from a region of higher temperature to a region of lower temperature without the actual movement of molecules is called conduction.

2. CONVECTION:

                 Convection is the flow of heat through a fluid from places of higher temperature to places of lower temperature by movement of thefluid itself.

3. RADIATION:

           Radiation can occur even in vacuum whereas Conduction and convection need matter to be present. Radiation consists of electromagnetic  waves travelling at the speed of light. Thus, radiation is the flow of heat from one place to another by means of electromagnetic waves. Transfer of heat energy from the sun reaches us in the form of radiation. Radiation is emitted by all bodies above 0K.

CONCLUSION:

       The transfer of heat or thermal energy will typically change the temperature of the substance, but not Always. For example, at the moment when the ice in the bowl turns to water those water molecules will be at the exact same temperature as when they were ice.