1. Section 1 The Nature of Waves

2. Waves carry energy without transporting matter.
any disturbance or movement that transmits energy through matter or space
Waves carry energy without transporting matter.

3. All waves are produced by something that vibrates.
Medium—a material through which a wave travels.
solid, liquid, or gas
Not all waves need a medium Ex: Electromagnetic waves

4. Types of Waves
3 kinds:
Transverse
Longitudinal
Surface

5. Transverse waves—waves in which the particles vibrate with an up-and-down motion. animation

6. Longitudinal waves—the particles in the medium vibrate back and forth along the path that the wave travels. animation

7. Surface waves- when a transverse and longitudinal wave combine.
Example: ocean waves

8. Section 2: Properties of Waves

9. How much energy they carry How fast they travel How they look
Ways waves differ
How much energy they carry
How fast they travel
How they look

10. n
Wavelength—the distance between any two adjacent crests or compressions in a series of waves.

11. Transverse waves have crests—the highest points, and troughs—the lowest points.

12. Longitudinal waves have dense regions called compressions and less dense regions called rarefactions.

13. Wavelength
Distance between one point on a wave and the nearest point just like it
Ex. crest to crest or trough to trough, compression to compression, rarefaction to rarefaction

14. Amplitude—the maximum distance the wave vibrates from its rest position.
The more energy a wave carries, the greater its amplitude.

15. Amplitude of longitudinal waves
denser compressions = larger amplitude = more energy the wave carries
less dense rarefactions = larger amplitude = more energy the wave carries A B

16. Amplitude of transverse waves
The distance from the crest or trough of a wave to the normal position of the medium

17. Frequency—the number of waves produced in a given amount of time
Frequency—the number of waves produced in a given amount of time. Expressed in hertz (Hz)

18. Higher frequency means more energy.
As frequency increases, wavelength decreases.

19. Wave speed is the speed at which a wave travels.
Wave speed (velocity) = wavelength x frequency

20. Light waves travel faster than sound waves.
Sound waves travel faster in liquids and solids than in gas.
Light waves travel faster in gases and empty space than in liquids and solids.

21. Light waves travel much faster than sound waves.
DISCUSSION QUESTION:
In a thunderstorm, why do you see the lightning before you hear the thunder?
Light waves travel much faster than sound waves.

22. Section 3: Wave Interactions
Reflection occurs when a wave strikes an object and bounces off of it.
All types of waves can be reflected.

23. Refraction—the bending of a wave caused by a change in its speed as it moves from one medium to another
greater change in
speed = more the
wave bends.

24. wave passes into a material that slows it down, it is bent toward the normal
wave passes into a material that speeds it up, it is bent away from the normal.

25. Diffraction—an object causes a wave to change direction and bend around it

26. If obstacle < wavelength, wave diffracts a lot.
If obstacle > than the wavelength, wave does not diffract much.
The larger the obstacle is compared to the wavelength, the less the waves will diffract.

27. Interference— two or more waves combine, form a new wave
Waves pass through each other, continue in their original direction
New wave exists only while the original waves continue to overlap.

28. Constructive interference—waves add together

29. Constructive Interference

30. Destructive interference—waves subtract from each other
D.I.

31. Destructive Interference

32. Standing waves—a wave pattern that stays in one place
Form when waves of = wavelength and amplitude traveling in opposite directions continuously interfere with each other.
Nodes—the places where two waves always cancel each other

33. Resonance—the ability of an object to vibrate by absorbing energy at its natural frequency