Conduction: Heat conduction (or thermal conduction) is the transfer of internal energy by microscopic diffusion and collisions of particles. The transfer of heat between two parts of a stationary system.The transmission of an electrical or chemical impulse along a nerve fiber. Convection: Heat transfer in a gas or liquid by the circulation of currents from one region to another. Heat transfer in a gas or liquid by the circulation of currents from one region to another Radiation: the process in which energy is emitted as particles or waves. joules: the standard unit of work or energy in the International System of Units (SI), equal to the work done by a force of one newton when its point of application moves through a distance of one meter in the direction of the force. calories: a unit of heat used to indicate the amount of energy that foods will produce in the human body.Also called gram calorie, small calorie. an amount of heat exactly equal to 4.1840 joules.The amount of a specific food capable of producing one thousand calories of energy.