2. 1

3. Recognize that all waves transfer energy. R e l a t e f r e q u e n c y & w a v e l e n g t h t o t h e e n e r g y o f d i f f e r e n t t y p e s o f e l e c t r o m a g n e t i c w a v e s & m e c h a n i c a l w a v e s. C o m p a r e a n d c o n t r a s t t h e c h a r a c t e r i s t i c s o f e l e c t r o m a g n e t i c a n d m e c h a n i c a l ( s o u n d ) w a v e s. E x p l a i n t h e p h e n o m e n a o f r e f l e c t i o n, r e f r a c t i o n, i n t e r f e r e n c e, & d i f f r a c t i o n. E x p l a i n t h e D o p p l e r E f f e c t i n t e r m s o f e v e r y d a y i n t e r a c t i o n s. Relate the speed of sound to different mediums. 2

4. Waves  Waves are disturbances that carry energy through matter or space. Clip Clip  The material does not actually travel with the wave….. only the energy is carried.  Waves can be visible or invisible evidence of energy transfer. 3

5. Types of Waves Two types of waves: Mechanical Non-Mechanical Mechanical: waves need a medium in order to travel. Examples: Sound, water Non-mechanical: waves do not need a medium to travel. Examples: light, gamma waves, microwaves, x-rays 4

6. Waves that require a medium to travel. Light waves are NOT Mechanical Waves. Sound and water. Mechanical Waves A medium is the material a wave travels through 5

7. Ways that waves travel Transverse waves –Water, light Compressional waves –sound 6

8. Transverse Waves  Transverse waves are UP & DOWN movements. EX: water waves, radio waves (all EM waves)  The displacement of individual particles is perpendicular (at right angles) to the direction of the wave. 7

9. Describing a Transverse Wave Crest Troug h 8

10. amplitude The higher the amplitude, the more energy the wave is carrying In a compressional wave- it’s how tightly the compressions are. 9

11. Frequency & Wavelength Wavelength Distance between to identical points on adjacent waves. Meters As the wavelength decreases the frequency increases Frequency Number of waves per second Hertz 10 λ

12. Movement of a Transverse Wave 911 CLIP

13. Example - Water Remember: Energy is transferred ---- NOT THE MATTER!-- 12

14. Compressional Waves Compressional waves are a series of PUSHES & PULLS in which the motion of the medium is in the same direction as the wave Ex. Sound Waves 13

15. Characteristics of a Compressional Wave 14

16. Parts of a Compressional wave Compressions & Rarefactions Rarefaction is a place where the atmospheric pressure is lowest. 15

17. Speed of a wave ν = f λ ν is the velocity (m/s) f is the frequency (hertz) λ is the wavelength (m) The speed of a wave changes as it moves through different media The speed of a mechanical waves is constant for any given medium.. 16

18. Let’s do some practice problems. ν = f λ

19. Wave interactions with matter

20. Reflection occurs when a wave hits another wave or object that it cannot pass through and bounces back. 17

21. Law of Reflection

22. 18 Refraction Refraction occurs when a wave passes from one medium to another at an angle and bends (changes direction) due to a change in speed.

23. Refraction

24. Diffraction is a wave phenomenon that is dependent on wavelength Light waves bend as they pass by the edge of a narrow aperture or slit Diffraction occurs when a wave passes through an opening and spreads out 19

25. Diffraction

26. When a wave encounters an obstacle. Apparent bending of waves around small obstacles and the spreading out of waves past small openings.

27. 20 Constructive Interference Constructive Interference occurs when two or more waves hit the same point and combine to produce a larger single wave. Destructive Interference Destructive Interference occurs when two or more waves hit the same point and combine to produce a smaller single wave.

28. Constructive Interference

29. Destructive Interference Clip

30. Recognize that all waves transfer energy. R e l a t e f r e q u e n c y & w a v e l e n g t h t o t h e e n e r g y o f d i f f e r e n t t y p e s o f e l e c t r o m a g n e t i c w a v e s & m e c h a n i c a l w a v e s. C o m p a r e a n d c o n t r a s t t h e c h a r a c t e r i s t i c s o f e l e c t r o m a g n e t i c a n d m e c h a n i c a l ( s o u n d ) w a v e s. E x p l a i n t h e p h e n o m e n a o f r e f l e c t i o n, r e f r a c t i o n, i n t e r f e r e n c e, & d i f f r a c t i o n. E x p l a i n t h e D o p p l e r E f f e c t i n t e r m s o f e v e r y d a y i n t e r a c t i o n s. Relate the speed of sound to different mediums. 2 GOALS REVISITED.