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55 Cards in this Set
- Front
- Back
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What is the definition of work?
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Mass or force over distance
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What is energy?
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Capacity to do work
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What is power?
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A powerful aphrodisiac.
Also, rate of energy flow/ rate of work done. |
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How long do you have to keep a 100-watt bulb burning to consume 1 kilowatt hour's worth of energy?
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10 hours.
(A kilowatt hour, or kWh, is equal to 1000 watts; it is a unit of energy equal to watts x hours.) |
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Name the three main fossil fuels we use.
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Petroleum, natural gas, and coal.
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What percentage of commercial energy worldwide is provided by fossil fuels?
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87%
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Which renewable energy source is most widely used?
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Hydroelectric
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What percentage of commercial power comes from renewable sources?
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7%
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What is a fossil fuel?
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Organic (carbon-based) compounds derived from decomposed plants, algae, and other organisms buried in rock layers for hundreds of millions of years.
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What is coal made of?
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Decomposed (fossil) plants
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What is oil made of?
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Decomposed (fossil) plankton
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Where does over 50% of the electrical energy in the U.S. come from?
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Coal-fired power plants
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What percentage of U.S. energy demands is supplied by oil?
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40%
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Where does over 99% of fuel for cars and trucks come from?
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Oil
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Which fossil fuel is most abundant?
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Coal. World coal deposits are ten times greater than conventional oil and gas resources combined.
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What are the four grades of coal?
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1. Peat
2. Llignite (brown coal) 3. Bituminous (soft black coal) 4. Anthracite. |
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What is carbonization?
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The process by which coal goes from peat to anthracite, losing water and volatile gases due to heat and pressure. The loss of the water and gases leads to an increased concentration of carbon.
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What is peat?
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-the earliest stage in the formation of coal.
-a histosol formed out of partly decayed plant material - harvested wet from bogs in places like Ireland, Scotland, and Finland -after it is dried it can be burned. -burns very dirtily and at a low heat, creating a lot of smoke and soot. |
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What is lignite?
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-aka "brown coal"
-second stage in formation of coal -more dried out than peat -burns dirtily (releases nitrogen oxides and sulfur oxides) and at a low heat -abundant in western U.S. |
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What is bituminous coal?
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-3rd stage in formation of coal
-comes in three grades (bituminous 1, 2, and 3) which are increasingly purer in carbon |
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What is anthracite?
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-4th and final stage in formation of coal
-burns at the hottest flame and with the least pollution -composed of over 90% carbon -lots of it in NE PA |
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What is a gasifier?
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-Used in cleaning up air pollution (see diagram in ppt: there is more info on there than I was able to put into flash cards).
-Byproduct: ash/slag, which is made into cinder blocks for construction. |
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What is Hubbert's curve?
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M.K. Hubbert used statistical methods to monitor U.S. oil production. Hubbert's curve is the line graph that represents annual oil production ascending to its peak and then descending over time. In 1959 he said that the U.S. would hit peak oil production in March 1979; he was only a few months off.
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How much of the world's known oil reserves have we used?
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Nearly half (over .5 trillion barrels)
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What was the "Atoms for Peace" speech?
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Dwight D. Eisenhower's 1953 speech to the UN announcing that the U.S. would start building nuclear-powered electric generators.
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What portion of U.S. nuclear power plants are approaching the end of their expected operational life?
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Half (52) of them are over 30 years old and therefore not expected to operate much longer.
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How does a nuclear reactor work?
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-Radioactive uranium atoms are unstable, i.e., they will undergo nuclear fission (splitting) when struck by a high energy neutron.
-This nuclear fission releases energy and more neutrons, creating a chain reaction releasing extremely intense heat that boils water. |
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How is thermal pollution caused and what are its effects?
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-Nuclear power plants generate so much heat that they need extensive cooling systems to keep the equipment from melting.
-Nuclear reactors are built on large bodies of water so that the water can circulate and cool off the reactors -When the heated water is dumped into local estuaries, and when such dumping ceases, the consequent fluctuation of the water temperature can adversely affect water quality and aquatic life. |
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What happened on Three Mile Island, and when?
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-3/28/1979 [slide says 1989; this was corrected in lecture]
-reactor on Three Mile Island underwent partial meltdown: cloud of steam containing radioactive gases escaped from reactor. -This raised the radioactivity of the surrounding environment, so people were evacuated from island. -Stalled the nuclear industry thereafter. |
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What are the three kinds of radiation?
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Alpha, Beta, and Gamma.
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What is alpha radiation?
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-helium nucleus with mass of 4 is emitted by radioactive decay of a nucleus (Uranium-238 decays, becoming Thorium-234 and Helium-4).
-heavy, slow particle -can be stopped by paper |
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What is beta radiation?
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-emission of an electron (e-) or positron (e+)
-caused when a neutron converts into a proton and an electron; the electron is then thrown out of the nucleus. -can be stopped by several sheets of aluminum foil |
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What is gamma radiation?
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-electromagnetic radiation of very short wavelength
-stronger than x-rays, very penetrative -can be stopped by several feet of lead |
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How is radioactive waste stored?
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-no safe storage method
-often stored temporarily on-site in pools or dry casks |
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Why is much of the energy we consume wasted?
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-much energy is released as heat
-there is a net loss of energy every time you change from one type of energy to another |
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What has been the trajectory of average gas mileage in the U.S. over the years?
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-doubled from 13 mpg in 1975 to 28.8 mpg in 1988
-by 2004 down to 20.4 mpg due to falling fuel prices, which discouraged further conservation |
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What are some ways to save energy and money?
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-minimize driving
-"Ride a bicycle, walk, and use stairs instead of elevators." (I tried riding a bike up the stairs but it totally didn't work. Screw conservation.) -keep thermostat low in winter, high in summer -buy fewer disposable items -turn stuff off when you're not using it -line-dry laundry -recycle -eat less meat -buy local food |
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What is our original source of biomass fuel?
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Firewood
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What are the two biofuels that are currently gaining in popularity and use?
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Ethanol and biodiesel
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Why is ethanol a good additive to gasoline?
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It is rich in oxygen and burns easily.
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What type of fuel has been promoted by both farm and energy policies in the U.S.?
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Biofuels (especially ethanol)
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What is the fastest-growing renewable energy resource?
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Wind energy. It could potentially produce up to 50 times the capacity of current nuclear energy production.
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What is a wind farm?
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Large concentrations of wind generators producing commercial electricity
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What are the basic pro and con of solar energy? (one of each)
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Pro: it is abundant
Con: it is diffuse |
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What is passive solar technology?
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Heat-absorbing floors or walls, or glass-walled "sun spaces," provide heat to a house simply by absorbing the sun's energy (no further mechanical component)
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What is active solar technology?
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Solar panels have piping connected to them; water or other fluid is heated at the site of the solar panel and then pumped throughout a house to heat it.
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What is a photovoltaic cell?
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-captures solar energy and converts it directly into electrical current
-still somewhat expensive |
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What has been the trajectory of water power use since the 19th century?
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-19th century: water turbines invented.
-By 1925: falling water generated 40% of world's electric power -Today: water generates only 25% of total electric power due to increase in fossil fuel use |
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What is tidal power?
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-Ocean tides and waves contain enormous amounts of energy
-Tidal power can supply energy in areas that have long bays with narrow mouths, e.g. Bay of Fundy |
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How might waves be harnessed to generate energy?
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Could supply power by pushing a turbine
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What is geothermal heat and how can it be used?
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-heat from Earth's core
-most available at plate boundaries: used in Iceland and in California -in areas other than plate boundaries, normal geothermal gradient can be used to heat homes -inexpensive, efficient, low environmental impact |
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What is a fuel cell?
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-A device that uses ongoing electrochemical reactions to produce an electrical current.
-Works something like a battery. |
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Name a pro and con of hydrogen fuel cells.
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Pro: no emissions or other impacts. only byproduct is water.
Con: relies on free hydrogen gas, which is highly explosive. |
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What is nuclear fusion?
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-Relies on welding of low atomic weight atoms to produce energy
-has to be done under extremely high temps: 100 million deg. F -e=mc^2: a little bit of matter can yield a whole lot of energy -could potentially yield an unlimited supply of energy, but is not yet economically feasible |
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Why is it a good idea for the energy supply to become more diverse, decentralized, and local?
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-many alternative energy sources are practical only in certain areas/conditions (wind, sun, etc). no one renewable resource that works well everywhere all the time.
-energy is lost/wasted when it is transferred. |
