The Importance of the Methods of Heat Transfer in Physical Science

Three Types

Radiation transfers the energy in an electromagnetic wave, without the source or the receiving surface having to be in contact. Conduction is the transfer of heat between two objects that touch. Convection is heat movement in a liquid or gas, including air. Each type of transfer has its place in nature and in man-made heating systems.

Convection is the means by which heat moves around through its environment. It is the basis for wind currents, such as storms, hurricanes and the movement of clouds. Convection through water also promotes water currents, which warm some coasts and ocean areas, providing an environment for creatures which prefer this temperature. Convection is also in progress when a cook heats liquids, spreading out the heat energy throughout the container. House radiators also work through convection, producing streams of warm air that move throughout the room.

Conduction is an important factor in the heat of the surface of the Earth. The uppermost part of the soil gains heat from the sun and the layers underneath conduct the surface heat underground. Conduction is also important for animals, who can lose body heat through touching a colder surface, such as humans with bare feet, or gain heat, in the case of animals such as snakes, by basking on a hot rock. In a man-made system, conduction is the way in which a house can lose heat through the walls to the outside, and materials that insulate, and therefore stop the heat conducting outward, help reduce this heat energy loss.

Radiation from the sun powers lots of important activities on Earth. For example, the heat in the radiation warms the surface of the planet on one hemisphere, depending on the time of day. This radiated heat, originating from nuclear fusion reactions in the sun, may then turn into convection heat through creating a temperature, and therefore density, difference between two or more areas of water or air, which then move around in currents. The heat in the radiation also adds energy to surface water, and evaporates it, thus feeding clouds, which turn into rain when the temperature then drops. Radiation is also man-made, such as direct heat radiation from fireplaces, which helps keep the people inside the home warm.