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Across 3. Distance between any point on the wave and equivalent point on the next 6. Time for one oscillation 9. This measures the depth of water under a boat 11. The sensation of a frequency is called a.... 12. A material that waves need to travel through is called.... 13. Sound above the range of human hearing are called.... 16. When waves bend around the sides of obstacle 18. Sound waves can be displayed using..... 19. Sound waves a re caused by... 20. Number of oscillations per second 21. Waves whose oscillations are up and down

Down 1. A bending effect caused by a change in speed 2. Regions of high pressure due to particles being close together in a longitudinal wave 4. Example of Longitudinal waves 5. The maximum distance a point moves from its rest position 7. When the oscillations are backwards-and-forwards the wave is ..... 8. Another name for vibration is.... 10. The SI unit of frequency 14. When the waves bounce off the surface at the same angle they strike it, is... 15. The speed of sound depends on.... 17. Reflected sound that comes a short time after the origninal