Portal:Energy
Portal:Energy
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In physics, energy (from Ancient Greek ἐνέργεια (enérgeia) 'activity') is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat and light. Energy is a conserved quantity—the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The unit of measurement for energy in the International System of Units (SI) is the joule (J).
Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object (for instance due to its position in a field), the elastic energy stored in a solid object, chemical energy associated with chemical reactions, the radiant energy carried by electromagnetic radiation, and the internal energy contained within a thermodynamic system. All living organisms constantly take in and release energy.
Due to mass–energy equivalence, any object that has mass when stationary (called rest mass) also has an equivalent amount of energy whose form is called rest energy, and any additional energy (of any form) acquired by the object above that rest energy will increase the object's total mass just as it increases its total energy.
Human civilization requires energy to function, which it gets from energy resources such as fossil fuels, nuclear fuel, or renewable energy. The Earth's climate and ecosystems processes are driven by the energy the planet receives from the Sun (although a small amount is also contributed by geothermal energy). (Full article...)
Hoover Dam is a concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between the U.S. states of Nevada and Arizona. Constructed between 1931 and 1936, during the Great Depression, it was dedicated on September 30, 1935, by President Franklin D. Roosevelt. Its construction was the result of a massive effort involving thousands of workers, and cost over 100 lives. In bills passed by Congress during its construction, it was referred to as the Hoover Dam, after President Herbert Hoover, but was named the Boulder Dam by the Roosevelt administration. In 1947, the name Hoover Dam was restored by Congress.
Hoover Dam impounds Lake Mead and is located near Boulder City, Nevada, a municipality originally constructed for workers on the construction project, about 30 mi (48 km) south-east of Las Vegas, Nevada. The dam's generators provide power for public and private utilities in Nevada, Arizona, and California. Hoover Dam is a major tourist attraction, with 7 million tourists a year. The heavily traveled U.S. Route 93 (US 93) ran along the dam's crest until October 2010, when the Hoover Dam Bypass opened. (Full article...)
Photo credit: Björn Appel
A solar furnace can be used to generate electricity, melt steel or make hydrogen fuel.
- If atmospheric greenhouse gas concentrations can be stabilized at 450 ppm, it is thought that there will be a 50% chance of avoiding dangerous climate change?
- The Itaipu hydroelectric power plant is currently the second largest power plant in the world, supplying over 90% of Paraguay's electricity, and 25% of Brazil's?
- Libya's Sirte Basin—which in some places lies more than 47 metres below sea level—contains roughly 80% of the country's known crude oil reserves?
- Approximately 95% of the electricity consumed by a normal incandescent light bulb (example pictured) is emitted as heat, rather than as visible light?
- Saudi Aramco is the largest oil corporation in the world and the world's largest in terms of proven crude oil reserves and production?
- Newcastle, Australia, is the world's largest coal export port?
- Surplus income from oil production in Norway is invested by the Government Pension Fund, one of the World's largest funds with a value of around US$ 800 billion?
- Energy superpowers Russia and Venezuela have, respectively, the world's largest reserves of natural gas and petroleum?
In 1831, Faraday began his great series of experiments in which he discovered electromagnetic induction. He established that a changing magnetic field produces an electric field, a relation mathematically modelled by Faraday's law. Faraday later used the principle to construct the electric dynamo, the ancestor of modern power generators. He went on to investigate the fundamental nature of electricity, concluding in 1839 that, contrary to opinions at the time, only a single "electricity" exists, and the changing values of quantity and intensity (voltage and charge) would produce different groups of phenomena.
Some historians refer to Faraday as the best experimentalist in the history of science. Despite this his mathematical ability did not extend so far as trigonometry or any but the simplest algebra. He nevertheless possessed the ability to present his ideas in clear and simple language. During his lifetime, Faraday rejected a knighthood and twice refused to become President of the Royal Society.
- "Our children will enjoy in their homes electrical energy too cheap to meter." – Lewis Lichtenstein Strauss, 1954
- "There is every possibility that you will soon be able to tax it." – Michael Faraday, talking to William Gladstone on the future purpose of electricity.
- "Higher energy prices act like a tax. They reduce the disposable income people have available for other things after they've paid their energy bills." – John W. Snow, 2005
- "Our dependence on foreign energy is like a foreign tax on the American people." – George W. Bush, 2005
WikiProjects connected with energy:
Other WikiProjects that may be of interest:
National energy supply, use & conservation
National electricity sector
Politics, economics, environment
- Climate change
- Energy conservation
- Energy economics
- Energy crises
- Energy development
- Energy policy
- Peak oil
Energy sources
- Fuels
- Biofuels
- Fossil fuels
- Fusion power
- Nuclear technology
- Renewable energy
- Energy conversion
- Electric power
- Energy storage
Energy-related design
Scientific usage
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