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.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with heat
Panasonic Starts Mass-Production of High-Capacity 3.1 Ah Lithium-ion Battery
16 hours ago |
not rated yet |
1
Panasonic Corporation developed a 18650-type high-capacity 3.1 Ah lithium-ion battery and began mass production of the battery this December. The new 3.1 Ah battery has a nickel positive electrode and an energy density of ...
Search results for heat
Hot Electrons Could Double Solar Cell Power Efficiency
17 hours ago |
4.7 / 5 (6) |
2
Scientists have experimentally verified a theory suggesting that hot electrons could double the output of solar cells. The researchers, from Boston College, have built solar cells that successfully use hot ...
Thermochemical nanolithography now allows multiple chemicals on a chip
Dec 16, 2009 |
4.5 / 5 (4) |
0
(PhysOrg.com) -- Scientists at Georgia Tech have developed a nanolithographic technique that can produce high-resolution patterns of at least three different chemicals on a single chip at writing speeds of ...
An Advance in Superconducting Magnet Technology Opens the Door for More Powerful Colliders
Dec 16, 2009 |
4.8 / 5 (11) |
0
(PhysOrg.com) -- Preparing for as much as a 10-fold increase in the Large Hadron Collider's luminosity within the next decade, U.S. scientists and engineers have demonstrated a powerful magnet based on an ...
Physicists see through the opaque with 'T-rays'
20 hours ago |
4.1 / 5 (9) |
0
"T-rays" may make X-rays obsolete as a means of detecting bombs on terrorists or illegal drugs on traffickers, among other uses, contends a Texas A&M physicist who is helping lay the theoretical groundwork to make the concept ...
Computer-simulated Thunderstorms with Ice Clouds Reveal Insights for Next-generation Computer Models
Space & Earth / Earth Sciences
15 hours ago |
4 / 5 (4) |
0
(PhysOrg.com) -- Computer simulations of thunderstorms using data from a field campaign in Australia confirm that the "ice-phase" cloud processes in climate models contribute most to the wide discrepancy between ...
Wild chimps have near human understanding of fire, study says
Dec 17, 2009 |
4.5 / 5 (8) |
0
(PhysOrg.com) -- The use and control of fire are behavioral characteristics that distinguish humans from other animals. Now, a new study by Iowa State University anthropologist Jill Pruetz reports that savanna ...
Review: Netbooks meet luxury in ultra-light Sony
Electronics / Consumer & Gadgets
Dec 16, 2009 |
3 / 5 (3) |
0
(AP) -- Netbooks have been a hit among laptop buyers because they're cheap and they're easy to carry. Now there's the option to pay a lot more and get a lot less - a lot less weight, that is.
African leaf-eating monkeys are 'likely to be wiped out' by climate change
16 hours ago |
2.6 / 5 (5) |
1
(PhysOrg.com) -- Monkey species will become 'increasingly at risk of extinction' because of global warming, according to new research published this week.
In a first, key pancreatic cells inserted in wounded airman's liver
Dec 17, 2009 |
5 / 5 (3) |
0
In what medical officials say is a first, the bullet-scarred pancreas from a service member who was shot in Afghanistan was flown from Walter Reed Army Medical Center in Washington to the University of Miami, where insulin-producing ...
Astronomers Find Super-Earth Using Amateur, Off-the-Shelf Technology (w/ Video)
Dec 16, 2009 |
5 / 5 (20) |
10
(PhysOrg.com) -- Astronomers announced today that they have discovered a "super-Earth" orbiting a red dwarf star 40 light-years from Earth. They found the distant planet with a small fleet of ground-based ...
List of search results for heat
