1. Waves What are they and how do they work?

2. Waves carry energy! There are 3 basic types. Mechanical Waves(sound) Electromagnetic Waves(light) Matter Waves(atomic particles)

3. Mechanical Waves Require a medium for the wave to propagate Require a medium for the wave to propagate Water Water Sound Sound Slinky Slinky Bridges Bridges

4. Electromagnetic Waves NO MEDIUM REQUIRED NO MEDIUM REQUIRED Travel at the speed of light (299,792,458m/s) Travel at the speed of light (299,792,458m/s) Radio waves Light x-rays Radio waves Light x-rays Microwaves Microwaves Gamma rays Gamma rays

5. Matter Waves Electrons and other particles show wave-like behavior. Electrons and other particles show wave-like behavior. This will not be covered in this course This will not be covered in this course

6. Mechanical Waves Are classified by the way that they move (displace) the medium they are in. Are classified by the way that they move (displace) the medium they are in. The three types of mechanical waves are: The three types of mechanical waves are: Transverse Transverse Longitudinal Longitudinal Surface Surface

7. Transverse Waves (light) Causes the medium through which the wave moves to move perpendicularly to the direction the wave is traveling Causes the medium through which the wave moves to move perpendicularly to the direction the wave is traveling Light waves travel in straight lines and do not need a medium Light waves travel in straight lines and do not need a medium

8. Longitudinal Waves(sound) Medium moves in the same direction as the wave Medium moves in the same direction as the wave Particles get compressed Particles get compressed Sound waves travel in all directions Sound waves travel in all directions

9. Surface waves Exhibit characteristics of both Transverse and longitudinal waves Exhibit characteristics of both Transverse and longitudinal waves Water wave Water wave

10. Keep in mind Even though particles in the medium of a mechanical wave move in response to the wave, they do not move along with the wave! Even though particles in the medium of a mechanical wave move in response to the wave, they do not move along with the wave! The wave only transfers energy The wave only transfers energy

11. Waves are a very effective means of transferring ENERGY! Define:TransmissionAbsorptionReflection

12. Vocabulary terms common to all waves.

13. Pulse A single disturbance that travels through a medium A single disturbance that travels through a medium

14. Periodic Wave A series of pulses moving in a regular repeating manner.

15. Things That All Waves Have in Common

16. Crest and Trough The crest is the high point The trough is the low point

17. Amplitude The amplitude of a wave is the distance from a crest to where the wave is at equilibrium. Amplitude is used to measure the energy transferred by the wave. The bigger the distance, the greater the energy transferred

18. Period (T) (in seconds) How long it takes one cycle of a wave to repeat itself.

19. Frequency (f) (in Hertz Hz) The amount of wave cycles per second f = 1/T therefore T = 1/f Find the frequency of a wave with a period of 0.5 seconds.

20. Wavelength ( λ ) (in meters) Distance between repeating parts of a wave Crest to crest Trough to trough

21. Phase Points on successive wave cycles of a periodic wave that are displaced by the same amount and in the same direction (away or towards) equilibrium, are said to be in phase.

22. Polarization of a Wave Any transverse wave can be polarized

23. Standing Waves Wave appears to be standing still as the result of identical waves moving in opposite directions Wave appears to be standing still as the result of identical waves moving in opposite directions Nodes Antinodes

24. Speed of a Wave Can be found by Can be found by v = λ/T = meters/seconds v = λ/T = meters/seconds therefore therefore v = f. λ v = f. λ The speed of any particular wave depends ONLY on the medium it is in. The speed of any particular wave depends ONLY on the medium it is in.

25. Wave Interaction: Superposition When Two Waves Meet, Two Things can happen

26. Constructive Interference When the peak of one wave matches up with the peak of another wave The new amplitude is the sum of the amplitudes of both waves http://www.problemsphysics.com/mecha nics/motion/animation/wave_propagatio n.html

27. ctive Interference Destructive Interference When the crest of one wave and the trough of another line up you have total destructive interference The level of destructive interference depends on how well they line up

28. Both Types of Interference Areas of maximum constructive interference

29. The Telltale Sign of a Wave! When this experiment is performed, and the result is the appearance of these “maxima”, you know that the thing in question moves as a wave. When this experiment is performed, and the result is the appearance of these “maxima”, you know that the thing in question moves as a wave. It turns out that this works for light too. It turns out that this works for light too. This led people to believe light travels as a wave! This led people to believe light travels as a wave!

30. Young’s Double Slit Experiment Distance between bright spots/band How far away screen is from slits Distance between slits Order of bands: first, second, third… Wavelength of light used

31. Incoming Wave d L Central Bright spot First Order Maxima xmxmxmxm λ Find the separation to the first order

32. Frequency Dictates Color