the laws of electromagnetism tell us that energy can be transferred from one object to another
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Answer:
Heat is the transfer of energy from a warmer object to a cooler object. For example, a lighted match (higher temperature object) will transfer heat to a large pan filled with lukewarm water (lower temperature object). Note that the actual amount of thermal energy each object has doesn't matter, as the pan of lukewarm water might have more thermal energy than the match. What is needed for heat transfer to take place is a difference in temperature between two objects. Without this difference, no heat transfer can take place.
Heat can be transferred in three ways: by conduction, by convection, and by radiation.
Conduction is the transfer of energy from one molecule to another by direct contact. This transfer occurs when molecules hit against each other, similar to a game of pool where one moving ball strikes another, causing the second to move. Conduction takes place in solids, liquids, and gases, but works best in materials that have simple molecules that are located close to each other. For example, metal is a better conductor than wood or plastic.
Convection is the movement of heat by a fluid such as water or air. The fluid (liquid or gas) moves from one location to another, transferring heat along with it. This movement of a mass of heated water or air is called a current.
Radiation is the transfer of heat by electromagnetic waves. When you stand in the sun, you are warmed by the electromagnetic waves, mainly infrared radiation (and to a lesser extent, visible light), that travels from the sun to Earth. In addition to the sun, light bulbs, irons, and toasters also transfer heat via radiation. Note that, unlike conduction or convection, heat transfer by radiation does not need any matter to help with the transfer.
You can detect evidence of heat transfer. You might see the air shimmering over a radiator (convection), put your hand on a warm spoon that's been sitting in a hot bowl of soup (conduction), or notice that the sun shine feels warm on your skin (radiation). If you need evidence of thermal energy or heat in your life, just feel your arm. Your body generates heat 24 hours a day! (Taken from KEEP Energy Education Activity Guide "Exploring Heat").
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