Related topics: power
Energy
hideIn physics, energy (from the Greek ἐνέργεια - energeia, "activity, operation", from ἐνεργός - energos, "active, working") is a scalar physical quantity that describes the amount of work that can be performed by a force, an attribute of objects and systems that is subject to a conservation law. Different forms of energy include kinetic, potential, thermal, gravitational, sound, light, elastic, and electromagnetic energy. The forms of energy are often named after a related force.
Any form of energy can be transformed into another form, but the total energy always remains the same. This principle, the conservation of energy, was first postulated in the early 19th century, and applies to any isolated system. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time.
Although the total energy of a system does not change with time, its value may depend on the frame of reference. For example, a seated passenger in a moving airplane has zero kinetic energy relative to the airplane, but non-zero kinetic energy relative to the Earth.
For more information about Energy, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with energy
Physics Model Determines Dynamics of Friends and Enemies
Dec 02, 2009 |
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(PhysOrg.com) -- Sometimes friends can become enemies and enemies become friends, and it’s difficult to understand exactly how or why the changes took place. A new study shows that when the shifting of alliances ...
Using superconducting probes to get a picture of what it's like inside CNTs
Nov 20, 2009 |
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(PhysOrg.com) -- "Carbon nanotubes are exciting for fundamental physics, and for potential technological applications," Nadya Mason tells PhysOrg.com. "However, we are generally limited in the way that we can study them. ...
Rice physicists find reappearing quantum trios
17 hours ago |
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Using atoms at temperatures colder than deep space, Rice University physicists have delivered overwhelming proof for a once-scoffed-at theory that's become a hotbed for research some 40 years after it first ...
Elusive 'hot' electrons captured in ultra-thin solar cells
20 hours ago |
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Boston College researchers have observed the "hot electron" effect in a solar cell for the first time and successfully harvested the elusive charges using ultra-thin solar cells, opening a potential avenue to improved solar ...
Researchers engineer bacteria to turn carbon dioxide into liquid fuel
Dec 10, 2009 |
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(PhysOrg.com) -- The genetically modified cyanobacterium consumes carbon dioxide and produces the liquid fuel isobutanol by using energy from sunlight.
Solar power coming to a store near you
Dec 10, 2009 |
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(AP) -- Solar technology is going where it has never gone before: onto the shelves at retail stores where do-it-yourselfers can now plunk a panel into a shopping cart and bring it home to install.
New techniques make carbon-based integrated circuits more practical
Dec 09, 2009 |
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(PhysOrg.com) -- Stanford engineers have built what they believe is a chip with the most advanced computing and storage elements made of carbon nanotubes to date by devising a way to root out the stubborn ...
At Stanford, nanotubes + ink + paper = equal instant battery (w/ Video)
Nanotechnology / Nanomaterials
Dec 07, 2009 |
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(PhysOrg.com) -- Stanford scientists are harnessing nanotechnology to quickly produce ultra-lightweight, bendable batteries and supercapacitors in the form of everyday paper.
Hunt for Higgs boson: Mass of top quark narrows search
Dec 07, 2009 |
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(PhysOrg.com) -- New high-energy particle research by a team working with data from Fermi National Accelerator Laboratory further heightens the uncertainty about the exact nature of a key theoretical component ...
Innovation puts next-generation solar cells on the horizon
Dec 01, 2009 |
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In a world first, a Monash University-led international research team has developed an innovative way to boost the output of the next generation of solar cells.
Large Hadron Collider sets new power world record
Nov 30, 2009 |
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(PhysOrg.com) -- CERN's Large Hadron Collider has today become the world's highest energy particle accelerator, having accelerated its twin beams of protons to an energy of 1.18 TeV in the early hours of the ...
Nanotube defects equal better energy and storage systems
Nanotechnology / Nanomaterials
Nov 19, 2009 |
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(PhysOrg.com) -- Most people would like to be able to charge their cell phones and other personal electronics quickly and not too often. A recent discovery made by UC San Diego engineers could lead to carbon ...
Turning heat to electricity... efficiently
Nov 18, 2009 |
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(PhysOrg.com) -- In everything from computer processor chips to car engines to electric powerplants, the need to get rid of excess heat creates a major source of inefficiency. But new research points the way ...
Ticking stellar time bomb identified (w/ Video)
Nov 17, 2009 |
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(PhysOrg.com) -- "One of the major problems in modern astrophysics is the fact that we still do not know exactly what kinds of stellar system explode as a Type Ia supernova," says Patrick Woudt, from the University ...
3-D microchips for more powerful and environmentally friendly computers
15 hours ago |
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Not so long ago our computers had a single core which had to be boosted for performance - making each machine into a great central heating system. Beyond 85° C, however, electronic components become unstable. ...
