Heat Project

H

eat is the energy that is transferred from one body to another due to temperature difference between the two bodies. Suppose you have an insulated bar with a temperature difference between its ends that is one end of the bar has higher temperature than the other end, we will say that the insulated bar will conduct energy along its length from the higher temperature to the low temperature ends.

This energy conducted from one point of the bar to the other is called thermal energy and will heart up the cold end of the bar and cool down the hot end of the bar. Now, if the situation continues eventually will reach a temperature along the bar where there will be no longer net flow of thermal energy along the bar. When this happens, the bar is in thermal equilibrium.

Thermal equilibrium is the state at which there is no net transfer of energy between parts of the system and as the results, all parts of the system are at constant temperature. (Note: this will happen provide no external interference with this system). You may ask yourself the term system means what, for the case of this topic the system is any part of the universe that has singled out for study (the part that we interested to study). Examples of the system material is an insulated bar. A system is said to be isolated if it is prevented from exchanging of thermal energy with the rest of the universe. A reader should not that if we take the surrounding and system we get the universe simplify mathematically:- 

Steady state is the constant rate of flow of thermal energy at constant temperature at a point but it is not in equilibrium. If your not carefully enough you may confuse the steady state and thermal equilibrium now, consider a thermal energy flowing along the bar as follows:-