What is Heat Transfer?
Heat transfer is the process of moving heat from a location where much heat exists to another location. In physics, it is taught this is mainly accomplished one of three ways: conduction, convection or radiation. In some ways, using this knowledge helps humans manipulate thermal energy in ways that are most beneficial. Understanding the principles behind heat transfer helps people do a number of activities more efficiently. From providing adequate heat in a home to providing options for cooking various foods, heat transfer plays a vital role in everyone’s lives. The uses of heat transfer are nearly endless. Conduction is one of the most common ways to transfer heat. This is done by transferring heat through matter from one atom to the next. It is most commonly experienced when a piece of metal, such as a cooking spoon, is left too long in a hot liquid. The heat will travel up the spoon. Some materials are more conductive than others, which is why metal pots often have rubber handles an
• Heat is warmth. In this lesson, we are dealing with heat or warmth from our sun. • Radiation is the method by which the sun’s energy reaches the earth. • Conduction is the direct transfer or movement of warmth and energy from one molecule to another molecule by collision. • Convection is the organized motion or movement of large groups of molecules based on their relative densities or temperatures.
Thermal energy is related to the temperature of matter. For a given material and mass, the higher the temperature, the greater its thermal energy. Heat transfer is a study of the exchange of thermal energy through a body or between bodies which occurs when there is a temperature difference. When two bodies are at different temperatures, thermal energy transfers from the one with higher temperature to the one with lower temperature. Heat always transfers from hot to cold. Table 1 shows the common SI and English units and conversion factors used for heat and heat transfer rates. Heat is typically given the symbol Q, and is expressed in joules (J) in SI units. The rate of heat transfer is measured in watts (W), equal to joules per second, and is denoted by q. The heat flux, or the rate of heat transfer per unit area, is measured in watts per area (W/m2), and uses q” for the symbol.
