Gateway 2

3. Gas usually found within the vicinity of petroleum reserves.
5. Energy created by friction between vibrating atoms and molecules.
8. The process of controlling resources; for example, limiting soil erosion, reducing sediment in waterways, conserving water, and improving water quality.
11. A resource that can be replaced when needed.
14. Energy associated with the flow of electrons.
16. The surroundings in which a person, animal, or plant lives.
18. The potential energy locked within a system and released during a chemical reaction.
19. Energy visible to the eye.
20. The first and simplest element on the periodic table. It is one of the most common elements in the galaxy.

1. Capable of being maintained at a steady level without exhausting natural resources or causing severe ecological damage.
2. An energy source that will never run out.
4. A machine for producing power in which a wheel or rotor is made to revolve by a fast-moving flow of water, steam, gas, or air.
6. The ability to bring a desired result with the least waste of time, energy, or material.
7. A resource that cannot be replaced once used.
9. The ability to do work. Energy can be converted from one form to another.
10. Energy produced by mechanical devices, such as gears, pulleys, levers, or internal combustion engines.
12. Substances discharged into the air (as by a smokestack or an automobile engine)
13. The flow of electrical power or charge.
15. The rate at which work is performed or energy is expended.
17. A measure of power equal to one joule of work per second.