Across
- 2. Energy that always changes from high to low quality forms
- 6. The energy stored in an object
- 7. Available in limited supply
- 8. A layer of material laid down naturally
- 9. A process in which resources can be renewed
- 10. The energy of motion
- 13. Convert crude oil into usable forms of oil
Down
- 1. A principle
- 3. Energy is neither created nor destroyed
- 4. A machine that generates electricity
- 5. A solid fossil fuel made up of almost pure carbon
- 7. Underground deposits of gas, mostly methane
- 11. To pollute
- 12. A thick liquid fossil fuel formed underground