ABSTRACT
Heat exchanges are crucial to our existence. Our bodies must balance heat loss and gain to stay within a narrow temperature range necessary for life – a delicate thermal balance from which deviations can have serious consequences. Heat then is internal energy in transit, and is measured in the standard SI unit, the joule. The idea that heat is actually a transfer of energy is the result of work by many scientists. The larger the specific heat of a substance, the more heat must be transferred to or taken from it to change its temperature by a certain amount. If heat is added to a gas at constant volume, the gas does no work on the environment because although it exerts a force on the container walls, they do not move. Heat transfer by infrared radiation is also important in maintaining our planet's warmth by a mechanism known as the greenhouse effect.
