ch 12-13 vocab

1. Fission: the splitting of an atomic nucleus into two smaller fragments, accompanied by the release of a large amount of energy.
2. Fusion: the joining of two lightweight atomic nuclei into a single, heavier nucleus, accompanied by the release of a large amount of energy.
3. Radioactive Decay: the emission of energetic particles or rays from unstable atomic nuclei; includes positively charges alpha particles, negatively charges beta particles, and high-energy, electromagnetic gamma rays.
4. Nuclear Reactor: a device that initiates and maintains a controlled nuclear fission chain reaction to produce energy for electricity.
5. Atomic Mass: the sum of protons and neutrons in the nucleus.
6. Atomic Number: the number of protons per atom.
7. Isotopes: forms of a single element that differ in atomic mass.
8. Radiation: a form of energy consisting of particles – tritium.
9. Spent Fuel: the used fuel elements that were irradiated in a nuclear reactor.
10. Passive Solar Heating: a system of putting the sun’s energy to use without requiring mechanical devices to distribute the collected heat.
11. Active Solar Heating: a system of putting the sun’s energy to use in which a series of collectors absorb the solar energy, and pumps or fans distribute the collected heat.
12. Convection: the circulation that occurs because warm air rises and cooler air sinks.
13. Photovoltaic Solar Cell: a wafer or thin film of solid state materials, such as silicon or gallium arsenide, that are treated with certain metals so that they generate electricity – that is, a flow of electrons – when solar energy is absorbed.
14. Solar Thermal Electric Generation: a means of producing electricity in which the sun’s energy is concentrated by mirrors or lenses onto a fluid-filled pipe; the heated fluid is used to generate electricity.
15. Fuel Cell: a device that directly converts chemical energy into electricity without the intermediate step of needing to produce steam and use a turbine and generator; the fuel cells requires hydrogen and oxygen from the air.
16. Biomass: plant and animals material used as fuel.
17. Biogas: converted biomass from animal wastes; usually composed of a mixture of gases (mostly methane) and is stored and transported like natural gas; a clean fuel; its combustion produces fewer pollutants than either coal or biomass.
18. Biogas Digesters: use microbial decomposition of household and agricultural wastes to produce biogas for cooking and lighting; the solid remains are removed from the digester and used as fertilizer.
19. Wind Energy: electric energy obtained from surface air currents caused by the solar warming of air.
20. Hydropower: a form of renewable energy that relies on flowing or falling water to generate electricity.
21. Methanol: a liquid converted from biomass (methyl alcohol) which can be used in internal combustion engines; produces relatively few pollutants.
22. Ethanol: a liquid fuel converted from biomass (ethyl alcohol) which can be used in internal combustion engines; mixed gasoline with 10% ethanol produces a cleaner-burning mixture called gasohol.
23. Hydrothermal Reservoir: formed when groundwater in volcanic areas travels downward and is heated, becoming buoyant and rises until it is trapped by an impermeable layer in Earth’s crust; contain hot water and possibly steam, depending on the temperature and pressure of the fluid.
24. Cogeneration: an energy technology that involves recycling “waste” heat.