| A | B |
|---|
| natural resource | any natural substance, organism, or energy form that living things use. |
| renewable resources | a natural resource that can be used and replaced over a relatively short time. |
| nonrenewable resources | a natural resource that cannot be replaced or that can be replaced only over thousands or millions of years. |
| recycling | the process by which used or discarded materials are treated for reuse. |
| energy resource | a natural resource that humans use to produce energy. |
| fossil fuel | a nonrenewable energy resource that forms in the Earth's crust over millions of years from the buried remains of once-living organisms. |
| petroleum | an oily mixture of flammable organic compounds from which liquid fossil fuels and other products are separated; crude oil. |
| natural gas | a gaseous fossil fuel. |
| coal | a solid fossil fuel formed underground from buried, decomposed plant material |
| strip mining | a process in which rock and soil are stripped from the Earth's surface to expose the underlying materials to be mined. |
| acid precipitation | precipitation that contains acids due to air pollution. |
| smog | a photochemical fog produced by the reaction of sunlight and air pollutants. |
| nuclear energy | the form of energy associated with changes in the nucleus of an atom; an alternative energy resource. |
| solar energy | energy from the sun |
| wind energy | energy from the wind |
| hydroelectric energy | electricity produced by falling water |
| biomass | organic matter, such as plants, wood, and waste, that contains stored energy |
| gasohol | a mixture of gasoline and alcohol that is burned as a fuel |
| geothermal energy | energy from within the Earth |
| fission | a process in which the nuclei of redioactive atoms are split and energy is released. |
| fusion | the joining of fnuclei of small atoms to form larger atoms. |
| solar cell | can change sunlight into electricity. |
| solar collector | dark colored boxes with glass or plastic tops that are used for direct heating or to generate electricity. |
| peat | first stage of coal |
| lignite | second stage of coal - formed from peat |
| bituminous | third stage of coal formed from increased heat and pressure on lignite |
| anthracite | fourth stage of coal - burns cleanest |
| channel | the path a stream follows |
| gradient | the change in elevation as the stream travels a distance |
| discharge | the amount of water a stream carries |
| load | the materials carried by a stream |
| deposition | the process by which material is dropped |
| alluvium | the rock and soil deposited by streams |
| delta | a fan-shaped body of land that forms at the mouth of a river where it enters another body of water |
| alluvial fan | fan-shaped deposits that form on dry land |
| floodplain | the land around a river that floods if the river overflows its banks |
