The thermal properties of matter are controlled by temperature. Temperature is a measure of the tendency of an object to absorb or dissipate energy in the form of heat. The heat capacity of a material defines the amount of energy that is needed to change its temperature. Conversely, heat capacity describes the temperature change that will occur with a given amount of energy. The typical engineering units for heat, a form of energy, are the British thermal unit (Btu) and the joule (J). In chemistry, however, the calorie (cal) is also used. Thermodynamics is the study of energy in transition. There are two basic physical laws of thermodynamics that can be applied to all processes involving heat, work, and energy. The first law of thermodynamics is commonly known as conservation of energy. The second law of thermodynamics describes the relationship of work and heat. Heat can be transferred between two objects in three modes: conduction, convection, and radiation.