Question

why is heat define as a form of energy

Answer 1

Heat is a form of energy that can be transferred from one object to another or even created at the expense of the loss of other forms of energy. To review, temperature is a measure of the ability of a substance, or more generally of any physical system, to transfer heat energy to another physical system.

Answer 2

because according to 1st law of thermodynamics heat can not be created or destroyed it only transfer from one body to another and heat is the medium to transform the energy ... and another one is work .. so i will give u tip to u understand better ..>>> energy is never destroyed or created because energy of all the universe is constant ..so hope its help !!