WAVES

2. the reduction of an item's density, the opposite of compression.
5. - time it takes something to happen
6. wave-a wave vibrating in the direction of propagation.
7. SI unit of length
12. International ( SI ) unit of time
13. - sensation of a frequency
15. - decrease in volume of any object or substance resulting from applied stress.
19. - lowest part of a wave
20. -phenomenon of increased amplitude that occurs when the frequency of an applied periodic force is equal.

1. - the spreading of waves around polarization
3. - maximum amount of displacement of a particle on the medium from its rest position.
4. -unit for expressing the ratio between two physical quantities,
8. - the change in direction of a wave passing from one medium to another caused by its change in speed.
9. speed- speed at which wave travels
10. wave-a wave vibrating at right angles to the direction of its propagation.
11. wave- wave with a repeating continuous pattern which determines its wavelength and frequency.
14. - electromagnetic radiation that can be detected by the human eye.
16. wave -a wave that is not capable of transmitting its energy through a vacuum.
17. - mechanical disturbance from a state of equilibrium
18. - how loud or soft a sound seems to a listener.