Across
- 2. harmful substance.
- 3. Fuels materials that formed as ancient plants and animals decayed underground.
- 5. an object that converts energy for human use with circular motion.
- 7. Energy Energy obtained from beneath Earth’s surface.
- 10. Gas a pollutant that increases the atmosphere’s ability to hold heat.
- 12. an unstable element used by humans as an energy source.
- 15. a device that reduces the amount of pollutants that get into the air.
- 16. Fuel an energy source made from unstable elements.
Down
- 1. is something made for a particular purpose.
- 2. a liquid fossil fuel formed by the decay of ancient plants and animals.
- 4. Gas a fossil fuel that occurs in the gas state.
- 6. stores chemical energy and can convert that energy into electrical energy.
- 8. Using energy of moving water.
- 9. a solid fossil fuel that is burned to transfer energy.
- 10. a device that changes energy of motion into electrical energy.
- 11. the release of substances into the environment.
- 13. is a material that releases energy as heat when it burns.
- 14. the process of burning fuel to produce heat and light.