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
Weather-sensitive architectural skins integrate form with function
Nov 06, 2009 |
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Buildings typically provide shelter from the elements, but one Ryerson University researcher thinks structures ought to relate more to the environment instead. To this end, she has created architectural "skins," ...
The greening of Willis Tower: Rooftop gardens part of plan to improve efficiency
Nov 06, 2009 |
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Growing up in the southwest suburbs, Sara Beardsley had a view of the Chicago skyline from her house. Today, she is transforming that skyline, but you won't find her work glorified on a $6 mug or gracing postcards.
New 'smart' electrical meters raise privacy issues
Nov 06, 2009 |
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The new "smart meters" utilities are installing in homes around the world to reduce energy use raise fresh privacy issues because of the wealth of information about consumer habits they reveal, experts said ...
Nocturnal wind maximum mapped for first time
Space & Earth / Earth Sciences
Nov 05, 2009 |
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On beautiful, sunny days with quiet weather conditions a strong wind develops in the evening at a height of about 200 metres.
Genomes of biofuel yeasts reveal clues that could boost fuel ethanol production
Nov 05, 2009 |
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As global temperatures and energy costs continue to soar, renewable sources of energy will be key to a sustainable future. An attractive replacement for gasoline is biofuel, and in two studies published online in Genome Re ...
Germany, Mexico, US top smart energy list
Nov 05, 2009 |
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Germany, Mexico and the United States have crafted some of the world's smartest policies for improving energy use, according to a study released on Thursday on the sidelines of the UN climate talks here.
Metal-Air Battery Could Store 11 Times More Energy than Lithium-Ion
Nov 05, 2009 |
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(PhysOrg.com) -- A spinoff company from Arizona State University plans to build a new battery with an energy density 11 times greater than that of lithium-ion batteries for just one-third the cost. With a ...
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 ...
Mimicking nature, scientists can now extend redox potentials
Nov 04, 2009 |
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(PhysOrg.com) -- New insight into how nature handles some fundamental processes is guiding researchers in the design of tailor-made proteins for applications such as artificial photosynthetic centers, long-range ...
Toward home-brewed electricity with 'personalized solar energy'
Nov 04, 2009 |
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New scientific discoveries are moving society toward the era of "personalized solar energy," in which the focus of electricity production shifts from huge central generating stations to individuals in their ...
Energy gap useful tool for successful weight loss maintenance strategy
Nov 04, 2009 |
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Americans continue to get heavier. Most weight control methods short of bariatric surgery are generally considered ineffective in preventing obesity or reducing weight. The term energy gap was coined to estimate the change ...
Will Europe Be Powered by the Sahara
Nov 04, 2009 |
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(PhysOrg.com) -- Europe has long been interested in developing alternative energy sources. And, one of the more interesting places that some Europeans are looking for solar power is the Sahara. With the vast ...
Flemish researchers develop revolutionary technology for use in plant breeding
Nov 03, 2009 |
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In collaboration with researchers at VIB-UGent and the University of Antwerp (Belgium), scientists at the BioScience business group of Bayer CropScience AG in Gent have developed a technology that can significantly increase ...
Powerful laser sheds light on fast ignition and high energy density physics
Nov 02, 2009 |
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A new generation of high-energy (>kJ) petawatt (HEPW) lasers is being constructed worldwide to study high intensity laser matter interactions, including fast ignition. Fast ignition is a laser-based technique ...
High-performance plasmas may make reliable, efficient fusion power a reality
Nov 02, 2009 |
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In the quest to produce nuclear fusion energy, researchers from the DIII-D National Fusion Facility have recently confirmed long-standing theoretical predictions that performance, efficiency and reliability ...
