Heat
hideIn physics and thermodynamics, heat is the process of energy transfer from one body or system to another due to a difference in temperature. In thermodynamics, the quantity TdS is used as a representative measure of the (inexact) heat differential δQ, which is the absolute temperature of an object multiplied by the differential quantity of a system's entropy measured at the boundary of the object.
A related term is thermal energy, loosely defined as the energy of a body that increases with its temperature. Heat is also loosely referred to as thermal energy, although many definitions require this thermal energy to actually be in the process of movement between one body and another to be technically called heat (otherwise, many sources prefer to continue to refer to the static quantity as "thermal energy"). Heat is also known as "Energy".
Energy transfer by heat can occur between objects by radiation, conduction and convection. Temperature is used as a measure of the internal energy or enthalpy, that is the level of elementary motion giving rise to heat transfer. Energy can only be transferred by heat between objects - or areas within an object - with different temperatures (as given by the zeroth law of thermodynamics). This transfer happens spontaneously only in the direction of the colder body (as per the second law of thermodynamics). The transfer of energy by heat from one object to another object with an equal or higher temperature can happen only with the aid of a heat pump, which does work.
For more information about Heat, read the full article at
Wikipedia.
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News tagged with heat
Solar power generation around the clock
Nov 05, 2009 |
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(PhysOrg.com) -- A Californian company, SolarReserve, is developing a solar power system that can store seven hours' worth of solar energy by focusing mirrors onto millions of gallons of molten salt, allowing ...
Inhibitor of Heat Shock Protein is a Potential Anticancer Drug, Study Finds
Oct 29, 2009 |
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(PhysOrg.com) -- Like yoga for office drones, cells do have coping strategies for stress. Heat, lack of nutrients, oxygen radicals - all can wreak havoc on the delicate internal components of a cell, potentially ...
A silo fire doesn't have to ruin all stored silage
Oct 27, 2009 |
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(PhysOrg.com) -- Sometimes, when harvest conditions are less than ideal, silage with lower-than-optimum moisture levels is put into a silo, potentially leading to excessive heating and a spontaneous-combustion ...
Scientists Develop New Method to Quantify Climate Modeling Uncertainty
Space & Earth / Earth Sciences
Oct 21, 2009 |
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(PhysOrg.com) -- Climate scientists recognize that climate modeling projections include a significant level of uncertainty. A team of researchers using computing facilities at Oak Ridge National Laboratory has identified ...
The future of electricity may be found in environmentally-friendly, thermoelectric cells
Oct 14, 2009 |
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The Air Force Office of Scientific Research and the National Science Foundation are funding research that may result in a military turbine aircraft that for the first time ever will produce its own electricity from exhaust ...
Hollow spheres made of metal
Oct 13, 2009 |
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Producing metallic hollow spheres is complicated: It has not yet been possible to make the small sizes required for new high-tech applications. Now for the first time researchers have manufactured ground hollow ...
Growth versus global warming
Oct 12, 2009 |
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(PhysOrg.com) -- Houses on stilts, small scale energy generation and recycling our dishwater are just some of the measures that are being proposed to prepare our cities for the effects of global warming.
Cosmic entropy could be 100 times greater than previously thought
Oct 06, 2009 |
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(PhysOrg.com) -- A new analysis of supermassive black holes has discovered the entropy of the universe is much greater than previously thought, which means it may also be very slightly closer to ultimate heat death.
Energy-autonomous sensors for aircraft
Oct 01, 2009 |
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Aircraft maintenance will be easier in future, with sensors monitoring the aircraft skin. If they discover any dents or cracks they will send a radio message to a monitoring unit. The energy needed for this ...
Warming, heat waves projected to grow worse with large regional variability
Space & Earth / Earth Sciences
Sep 30, 2009 |
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(PhysOrg.com) -- While long-term projections call for higher temperatures and heat waves even more intense than previously thought, considerable geographic variability is also in the forecast, according to a study published ...
Climate talks resume in Bangkok with deal in doubt
Sep 26, 2009 |
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(AP) -- Two years ago, governments from around the world came together on the island of Bali and agreed to urgently rein in the heat-trapping gases blamed for deadly heat waves, melting glaciers and rising ...
Computation helps predict heat transfer in diamond
Sep 22, 2009 |
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(PhysOrg.com) -- Cornell researcher Derek Stewart and collaborators have calculated the exact mechanism by which diamond conducts heat, a breakthrough that could lend insight into many fields, including electronics.
Targeted heat therapy offers new standard treatment option for soft tissue sarcoma
Sep 22, 2009 |
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Patients with soft-tissue sarcomas at high risk of spreading were 30% more likely to be alive and cancer free almost three years after starting treatment if their tumours were heated at the time they received chemotherapy, ...
New NASA Image Shows Extent of Station Fire Burn
Space & Earth / Space Exploration
Sep 09, 2009 |
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On September 6, 2009, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra satellite captured this simulated natural color image of the Station fire, burning ...
Farmers warned to get ready as climate change threatens crops
Sep 07, 2009 |
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Even if global temperatures rise slowly, climate change could slash the yields of some of the world's most important crops almost in half, according to a new study co-authored by an N.C. State University scientist.
