1. ON A SEPARATE PAPER TO TURN IN
QQ:
ON A SEPARATE PAPER TO TURN IN
What is energy?
Make a list of the major forms of potential energy. Make a list of the major forms of kinetic
What do all mechanical waves need to exist?
Sketch a longitudinal wave. Label its parts. Draw an arrow to show how the energy moves through the wave.
Draw a picture of a surface wave. Draw arrows to show how energy moves through them.

3. Today’s Objective:
I understand how energy travels through waves.

4. Vibrates at right angle to motion
Transverse Wave
Crest: highest point above the resting place
Trough: lowest point below rest
Vibrates at right angle to motion

6. Frequency: the number of complete cycles in a given time
Depends on how fast the object is vibrating

7. Measured in cycles per second
Unit: hertz (Hz)
1 Hz
2 Hz

8. Parts of wave:
Amplitude: maximum displacement from rest

9. Who will make the biggest splash?

10. More energy = greater amplitude

11. Wavelength

12. Increasing frequency 
decreases wavelength

13. Riding the Waves

14. How fast a wave is traveling
Wave Velocity:
How fast a wave is traveling
Vw= f
Vw = wave’s velocity
f = frequency
= wave length

15. 16) Liam shook 1 end of a robe
16) Liam shook 1 end of a robe. It vibrated to produce a wave with a wavelength of 0.25 meters. The frequency of the wave is 3.0 hertz. What is the speed of the wave?
Wave length = l = .25 m
Frequency = 3.0 hz
Wave velocity = ?
Vw = l f
Vw =.75m/s
Vw =.25m(3/s)

16. Vw f 1 2 Create a data table like the one below: Trial Time 10 Xs
Distance
To chair
Wave
Length f Vw 1 2

17. 1. Tie one end of the rope to a chair.

18. 2. Have one person shake the other end to send waves down the rope.

19. 3. With a partner, measure the time it takes your hand to move back and forth ten times. Record this time.

20. 4. Measure and record the distance from your hand to the chair.
5. Measure and record the time it takes a wave crest to travel this distance.

21. 6. Shake the rope again and measure only this time more rapidly
6. Shake the rope again and measure only this time more rapidly. Record the time it takes you hand to move back and forth ten times.
7. Measure and record the time it takes a wave crest to travel this distance.

22. 8. Calculate the frequency of the waves in your first and second and trial. Record your data in the table.
Divide 10 waves by the time it took to make them.

23. 9. Calculate the wave speed for trials one and two. Record the data.
Use the formula.

24. How was wave speed affected by increasing the frequency?
Drawing Conclusions:
How was wave speed affected by increasing the frequency?

25. waves bounce off a surface No change in speed or frequency
Reflection:
waves bounce off a surface
Hyperlink reflection on cat and mirror
No change in speed or frequency

26. Bending from entering a new medium So what’s happening here?
Refraction:
Bending from entering a new medium
So what’s happening here?
Due to a change in speed
Hyperlink on picture to refraction

27. Outer wheel travels farther;
Time is same for both paths.
…speed of outer wheel
is faster

28. Diffraction: Bending around an object
Hyperlink picture to video

29. More diffraction if:
* wave longer than opening
* bigger obstacle

30. 2 Kinds of Wave Interference:
Constructive
Destructive

31. Constructive interference:
2 or more combine
greater amplitude

32. Destructive interference: 2 or more combine smaller or no amplitude
Hyperlink video on picture

34. What is the frequency of a wave that has a wavelength of 250 m and a speed of 4230 m/s?
Vw = f l
Vw = 4230 m/s
4230m/s =f 250m
l = 250 m
4230m/s = f 250m
16.92Hz =f
16.92/s =f

35. Today’s Objective:
I understand the characteristics of the electromagnetic spectrum.

36. Need a medium to move through
Mechanical Waves:
Need a medium to move through
Transverse
Longitudinal

37. Did you see that?
15 min