There are countless examples of heat transfer, such as burning skin by holding a hot pan, boiling milk, or heating food in a microwave. When there is a temperature gradient, heat transfer can occur in three ways: conduction, convection, and radiation. Conduction is the process in which heat is transferred from a hot region to a cold region within an object, or between two objects in physical contact. For example, if a pan is placed above a fire, heat will transfer to the pan, and eventually, it becomes hot. Further, if one end of a steel spoon is placed above a fire, the other end becomes hot due to heat transfer. In conduction, the molecules of the hot side have higher kinetic energy. They collide with the molecules of the colder region and transfer energy. The rate of heat transfer through conduction is given by an equation involving temperature gradient, surface area, and thickness of the material that heat flows through. 'k' is the material's thermal conductivity, which is high for conductors and low for insulators.