1. As part of thermodynamics, a measure of the amount of energy transferred from one body to another because of the temperature difference between those two bodies.
2. The temperature of a body, substance, or physical environment; especially, a relatively high temperature.
3. A form of transferred energy that arises from the random motion of molecules and which is felt as temperature; especially, as warmth or hotness.

Heat is transmitted by conduction, convection, or radiation.

A machine that converts heat into sound energy and then into electrical energy without the use of mechanical parts: Martin was devising an acoustic heat engine which he believed would bring much less expensive electricity to many people in his city.

The high temperature generated by humans or by their activities; such as, the heating and cooling of buildings, the operation of machinery, appliances, and transportation vehicles; as well as, various industrial and manufacturing processes.

A heat transfer from south to north by near-surface waters moving across the equator in the Atlantic Ocean: The Atlantic heat conveyor is a movement that is necessary to stabalize a southward flow of water in the deepness of the ocean, which is slow-moving with a cold and substantial current.

Any method or process in which electric energy becomes heat energy by resisting the free flow of electric current; such as, radiant heating.

1. The specific heat contributed by the motion of conduction electrons in a conductor.
2. A contribution to the specific heat of a metal from the motion of conduction electrons.

1. Energy in the form of natural heat flowing outward from within the plant Earth and contained in rocks, water, brines, or steam: Geothermal heat is produced mainly by the decay of naturally occurring radioactive isotopes of thorium, potassium, and uranium in the Earth's core.

Geothermal energy is produced by tapping the Earth's internal heat. At present, the only available technologies to do this are those that extract heat from hydrothermal convection systems, where water or steam transfer the heat from the deeper part of the Earth to the areas where the energy can be tapped.

The amount of pollutants found in geothermal vary from area to area but may contain arsenic, boron, selenium, lead, cadmium, and fluorides. They also may contain hydrogen sulphide, mercury, ammonia, radon, carbon dioxide, and methane.

Getting the Earth's Heat

Geothermal power plants, which tap hot subterranean water or steam, are high on the lists of at least thirty states in the U.S. which are requiring utility companies to generate some portion of their electricity from such renewable sources.

Most utilities have not pursued geothermal energy primarily because up-front costs, including exploratory drilling, can be expensive since geothermal taps deep reservoirs, not groundwater, which collects much closer to the surface.

An extensive study recently released by the Massachusetts Institute of Technology has shown that the heat available under ground is surprisingly plentiful nationwide.

More information about special Geothermal Energy sources.

Heat pumps which consist of underground coils that transfer heat from the ground to the inside of a building: The large company had a ground source heat pump to heat and to cool their many buildings.

1. Coagulation of muscle protein as a result of heat.
2. Etymology: from Old French rigor, from Latin rigorem, rigor, "numbness, stiffness", from "heat" + rigere, "to be stiff".

1. Thermodynamics, in which a constant which expresses the number of units of heat in terms of a unit of work, typically expressed as the amount of heat transfer required to raise the temperature of one gram of water from 14.5 to 15.5 degrees centigrade.
2. The amount of mechanical energy equivalent to a unit of heat.
3. The number of units of work or energy equal to one unit of heat; such as, 4.1858 joules, which equals one small calorie.

The principle of heat which consists of motions of the particles that make up a substance.

The use of solar thermal technologies to produce hot air, water, or steam for industrial purposes, generally at temperatures below 250 degrees centigrade.

1. A combination of thermal cells.
2. A voltage source consisting of a number of bimetallic junctions connected to produce a voltage when heated by a flame.
3. A high-temperature, molten-salt primary battery in which the electrolyte is a solid, non-conducting inorganic salt at ambient temperatures.d

When power is required, an internal pyrotechnic heat source is ignited to melt the solid electrolyte which allows electricity to be generated electrochemically for periods from a few seconds to an hour.

This process is often used for military applications; such as, missiles, torpedoes, and space missions.

1. Heat stroke resulting from the prolonged exposure to the sun, characterized by extreme pyrexia, prostration, convulsion, and coma.
2. A severe and often fatal illness produced by exposure to excessively high temperatures; especially, when it is related to significant physical exertion.

It is usually experienced with elevated body temperature, lack of sweating, hot dry skin, and neurologic symptoms; including unconsciousness, paralysis, headache, vertigo, and/or confusion. In severe cases, very high fever, vascular collapse, and coma also develop.

1. Subject to alteration or destruction by heat.
2. Unstabilized or destroyed when exposed to high temperatures.
3. Easily altered, destroyed, or decomposed by heat.

The portion of the energy input to a mechanical process that is rejected into the environment: There is something ironic about air conditioners that cool a person's home but which generate a lot of waste heat which is poured out into the environment.

Any system or process that actively captures warmth which would otherwise be discharged into the environment, so that it can be used for other purposes: The use of the heat from exhaust gases to heat water is an example of waste heat recovery.