Stretch and Challenge Crossword:

3. Sound above 20,000Hz, Outside the range of human hearing.
5. Part of a power plant that transfers kinetic energy into Electricty.
6. The 'crest' of a longitudinal wave.
9. A result of burning fossil fuels that is caused by increase Carbon Dioxide in the atmosphere.
10. The speed of sound in air.
13. A way of transferring electricity into gravitational potential energy.
17. Colour that is best at absorbing IR radiation.
18. A potential disadvantage of wind power.
19. The distance between a peak and rest point.
24. The unit of frequency.
28. A wave that oscillates parallel to the direction of energy transfer.
29. The time it takes for installing insulation to cover the cost of instillation.
30. A quantity measured in kilograms.
31. the distance between two peaks of a wave.
32. The unit of energy.
33. A result that doesn't fit the expected pattern.

1. When a wave changes direction after reaching a boundary.
2. The medium sound waves travel fastest in.
4. the energy required to raise 1kg of a subustance in temperature by 1 degree celcius.
7. A wave that oscillates at right angles to the direction of energy transfer.
8. Energy resources that come from decomposed animal and plant matter.
11. A liquid or gas that flows to fill a container.
12. transfers water's gravitational energy store into an electrical energy store.
14. Energy resources that can't be used up.
15. Heat transfer that takes place in fluids.
16. heat transfer that is faster when free moving electrons are present.
20. A way of reducing energy dissapation.
21. energy resource using fission.
22. When a wave bounces off a surface.
23. The unit of power.
25. A renweable energy resource that uses burning plant matter such as trees.
26. The 'trough' of a longitudinal wave.
27. the time it takes for a whole wave to pass a certain point.