1. Waves!
…Of all kinds

2. What are waves?
Wave – Energy that is transferred through a medium, or a source.
What’s energy?
The ability to do work.

3. There are two kinds of waves
Mechanical
Electromagnetic

4. Mechanical Waves Ex. Ocean Waves Need a medium:
a material through which a wave travels.
Note this is only true for mechanical waves
Electromagnetic waves can travel through space!

5. How do waves transfer energy?
Do waves move material?
Yes, but not the way you think it does.
Material does not move in the same direction as the energy.
Have you ever gone to the beach and waited for a good body surfing wave?

6. Waves Wave motion The wave moves water up and back toward the crest
Then down and forward toward the trough.
Water moves in little circles!
Only the energy moves.
WATCH!

20. What causes waves?
Mechanical waves are produced when a source of energy causes a medium to vibrate.
AKA, A disturbance!

21. Types of Mechanical Waves
There are two kinds:
Transverse
Longitudinal
Rope exercise.

22. Transverse Waves
Properties of a transverse wave

23. Longitudinal Waves
Also known as compression waves
Slinky exercise

24. Longitudinal Waves
Properties of longitudinal waves.

25. Longitudinal Waves Parts of longitudinal waves. Compression
Rarefaction

26. Electromagnetic Waves
Do not need a medium
Examples: X-Rays, Gamma Rays, Microwaves, Light Waves, and Radio Waves.

27. Wave Properties
Amplitude
Wave Length
Frequency
Speed

28. Wave Properties
Amplitude, wavelength, frequency, speed

29. Amplitude A measure of how high the crest is from rest position
Or a measure of the intensity of the compression

30. Wavelength
The distance from crest to crest, or trough to trough

31. Wavelength
Or from the center of one compression or rarefaction to the center of the next compression or rarefaction

32. Frequency and Speed Frequency:
How many waves pass a point in a given amount of time.
Example: on the beach you may average 3 waves each minute. What’s the waves frequency?

33. Speed Speed – How fast the wave is moving.
It is closely related to frequency

34. Wave Speed To calculate wave speed you need to know
Wavelength (distance between waves)
Measured in Meters (m)
Wave Period (time it takes for two crests to pass a particular point
Measured in Seconds (s)
OR Wave Frequency (# waves that pass a point in a given amount of time.)
Speed= distance/time (S=d/t) so…
S= wavelength /period OR S= (wavelength)(Frequency)

35. Try One
A wave has a frequency of 3 waves per second. What is its speed if its wave length is 3 meters?
4 waves pass a fixed point in 2 seconds. If the wave has a wave length of 3 meters, what is its speed?