heat

Heat is a form of energy that is typically transferred from hotter objects to cooler objects. It arises due to the movement of molecules and atoms within a substance. The total amount of heat transferred is often measured in units of joules or calories. Heat can have a significant impact on the properties and behavior of materials, including their temperature, state of matter, and chemical reactions. It plays an important role in many natural and human-made systems, from the sun's energy sustaining life on Earth to the operation of power plants and heating systems.