1. Waves Parts, Types, and Interactions

2. Definition of a Wave A disturbance that travels through a medium from one location to another location. Waves transfer energy from one place to another.

3. Longitudinal Waves Medium travels parallel to direction of wave propagation. (sound, p-waves)

4. Transverse Waves Medium travels perpendicular to direction of wave propagation. (light, s-waves)

5. Types of Waves

6. Water Waves (swell) Water waves are the superposition of longitudinal and transverse motions of water molecules. Individual water molecules travel in circles.

7. Wave Parameters Wavelength ( ) length or size of one oscillation Amplitude (A) strength of disturbance (intensity) Frequency (f) repetition

8. Wave Parameters

9. Wave Properties Waves are oscillations that transport energy. The energy of a wave is proportional to its frequency. Fast oscillation = high frequency = high energy Slow oscillation = low frequency = low energy The amplitude is a measure of the wave intensity. SOUND: amplitude corresponds to loudness LIGHT: amplitude corresponds to brightness

10. Wavelength Measure from any identical two successive points 510152025303540

11. Wavelength Measure from any identical two successive points 510152025303540 30 - 10 = 20

12. Wavelength Measure from any identical two successive points There are 4 complete oscillations depicted here ONE WAVE = 1 COMPLETE OSCILLATION 510152025303540 22.5 - 2.5 = 20

13. Frequency Frequency = number of WAVES passing a stationary point per second (Hertz)

14. Remember… Frequency (f) = number of oscillations passing by per second Period (T) = length of time for one oscillation T = 1/ff = 1/T

15. Wave Speed Wave speed depends on wavelength and frequency: v =  f Which animal can hear a shorter wavelength? Cats (70,000 Hertz) or Bats (120,000 Hertz) = v/f

16. Wave Speed = v/f Higher frequency = shorter wavelength Lower frequency = longer wavelength

17. Wave Interference Waves add constructively.

18. Wave Interference Waves add constructively.

19. Wave Interference Waves cancel destructively.

20. Wave Interference Waves oscillate “out of phase”. ½ wavelength phase shift

21. Wave Interference

22. Waves at a Boundary Reflection: waves “bounce” off barrier.

23. Waves at a Boundary Reflection: Waves will always reflect in such a way that the angle at which they approach the barrier equals the angle at which they reflect off the barrier

24. Waves at a Boundary Refraction of waves involves a change in the direction of waves as they pass from one medium to another

25. Waves at a Boundary Diffraction involves a change in direction of waves as they pass through an opening or around a barrier in their path.

26. Waves at a Boundary animations