1. Warm Up 1. How are longitudinal wavelengths measured?
2. How do you find the frequency of a wave?
3. Wave speed depends on the ____________.
4. What type of objects do wave travel fast in? How about slow?

2. Chapter 14-2, 14-3
Wave Interactions

3. Doppler Effect: Pitch is determined by frequency
Pitch – High or low the sound is
Frequency changes when the source of the wave is moving

5. Doppler Effect
Doppler Effect – Change in the frequency (pitch) of a wave when the source or the observer is moving

8. Reflection Reflection - a wave strikes an object and bounces off of it
All waves:
Light
Sound
Water

9. Wave Interactions:
Reflection – Bouncing back of a wave (Sound, Light, or Heat)
Waves bend around an edge

10. Echoes Sound waves bouncing back (or reflecting) towards you.
Yelling in a cave!

12. The Law of Reflection
Incident beam – light beam that strikes the mirror
Reflected beam – light beam that bounces off the mirror

13. The Law of Reflection
Normal – line perpendicular to surface of the mirror
Angle of incidence = Angle of refection

15. Refraction As light changes mediums – it changes speed
Refraction - bending of a wave caused by a change in its speed as it moves from one medium to another

16. Wave Interaction:
Different substances have different wave speeds

17. Refraction

18. Refraction

20. Diffraction
Diffraction - causes a wave to change direction and bend around it.
Waves pass around an object.

21. Wave Diffraction

23. Diffraction of Radio Waves
AM radio waves - longer wavelengths
FM radio waves – shorter wavelength
AM gets better reception

25. Interference
Interference - Two or more waves overlap and combine to form a new wave

26. Constructive Interference
Waves add together
Crests of two or more transverse waves arrive at the same place at the same time and overlap

27. Constructive Interference
Amplitude = sum of 2 waves

29. Destructive Interference
Destructive interference - waves subtract from each other as they overlap

31. Standing Waves
Standing waves – a wave pattern of vibration that simulates a wave that is standing still

32. Nodes and Anti-Nodes

33. Standing Waves:
A pattern of vibration that simulates a wave that is standing still
Nodes – Point that separates the loops in a standing wave and has no vibration – Complete Destructive Interference
Antinodes – Points of maximum vibration – Complete Constructive Interference