Introduction to Types of Waves Including questions for einstruction student responders using CPS software.

1. Integrated Science
Unit 4, Chapter 12

2. Waves are everywhere in nature
Sound waves, telephone chord
visible light waves,
waves, stadium waves,
radio waves, earthquake
microwaves, waves,
water waves, waves on a
string,
slinky waves
2

3. 12.1 Why study about waves?
useful puzzling

4. What is a wave?
Read intro page 201
*A wave is a disturbance that travels
through a medium from one location
to another.
*A wave is the motion of a
disturbance
Examples: Waves in water; Seismic
waves in the Earth
4

5. 12.1 Waves Read page 201
 If we poke a ball floating on
water, it will bob up and down
(harmonic motion).The
oscillating ball creates a wave
on the water surface.
— What is oscillation?
Oscillation is a system of
harmonic motion The first ball
can make a second ball that is
farther away oscillate. (move)
 Explain the transfer of energy.
Water Demo

6. 12.1 Waves Read page 201
 *Harmonic Motion: Motion that
repeats itself. Like a ball
bobbing up and down in the
water
 *What is oscillation?
Oscillation is a system of
harmonic motion
Example: The first ball can
make a second ball that is
farther away oscillate. (move)
Water Demo

7. Read page 202
12.1 Evidence of waves
 Anytime you see a vibration that moves
 Anything that makes or responds to sound
 Anything that makes or responds to light
 Anythingthat transmits information through the air
(or space) without wires
— cell phones, radio, and television.
 Anything that allows you to “see through” objects
— ultrasound, CAT scans, MRI scans, and X rays

8. 1. When you transmit information
without anything obviously moving,
you are using waves.
A. Yes
B. No

9. 2. How many different types of waves
are there?
2.0
0.1

10. There are Two Types of Waves:
1. *A transverse wave has its oscillations
perpendicular to the direction the wave
moves.
(In other words: the wave bobs up and down)
Read page 203

13. 3. [Enter question here]
A. True
B. False

14. There are Two Types of Waves:
2. *A longitudinal wave has its
oscillations in the same direction as the
wave moves.
Read page 203

15. *Longitudinal Wave
The wave we see here is a longitudinal wave.
The medium particles vibrate parallel to the
motion of the pulse.
*This is the same type of wave that we use to
transfer sound.
Can you figure out how??
 show tuning fork demo
15

18. Compare/Contrast Wave Types
The difference between the two types:
18

19. These are transverse waves.
A. True
B. False
19

20. This is a transverse wave:
A. True
B. False
20

21. Sound travels through a
longitudinal wave.
A. True
B. False
21

22. Read page 204
Anatomy of a Wave
Now we can begin to describe the
anatomy of our waves.
We will use a transverse wave to describe
this since it is easier to see the pieces.
22

23. *Anatomy of a Wave
*In our wave here the dashed line represents the
equilibrium position.
Once the medium is disturbed, it moves away
from this position and then returns to it
23

24. Anatomy of a Wave
crest
The points A and F are called the CRESTS
of the wave.
*The crest is the point where the wave
exhibits the maximum amount of positive or
upwards displacement. (the top of the
wavelength)
24

25. Anatomy of a Wave
trough
The points D and I are called the
TROUGHS of the wave.
*The troughs are the points at the bottom
of wavelength)
25

26. Anatomy of a Wave
Amplitude
*The distance between the dashed line and
point A is called the Amplitude of the wave.
This is the maximum displacement that the
wave moves away from its equilibrium.
26

27. Anatomy of a Wave
wavelength
The distance between two consecutive similar
points (in this case two crests) is called the
wavelength.
*The wavelength is the length of the wave pulse.
Between what other points is can a wavelength be
measured?
27

28. 4. There are two ways to
measure a wave: from crest to
crest
A. Trueor trough to trough.
B. False
28

29. Wave frequency
We know that frequency measure how
often something happens over a certain
amount of time.
We can measure how many times a pulse
passes a fixed point over a given amount
of time, and this will give us the
frequency.
29

30. Wave Frequency
* The frequency of a wave is a measure
of how often it goes up and down.
*Wave frequency is measured in hertz.
30

31. Frequency, Amplitude and
Wavelength

32. 12.1 Wavelength

33. *Speed of a Wave:
frequency (cycles/sec)
*speed (m/sec) v=fl
wavelength (m)

34. 5. What is the speed of a wave that
has a frequency of 10 hz and a
wavelength of 50 m?
500.0
0.1

35. 6. What is the speed of a wave that
has a frequency of 5 hz and a
wavelength of 30 meters?
150.0
0.1

37. The frequency of a wave is how often
it goes up and down.
A. True
B. False

38. The amplitude of a wave is the
largest amount it goes above or
below the equilibrium.
A. True
B. False

39. Waves are measured in joules.
A. True
B. False

40. Waves transfer energy through the
disturbance of a medium.
A. True
B. False

41. Frequency is the measurement of
height of a wave.
A. True
B. False

42. Sound is carried through transverse
waves.
A. True
B. False

43. Your Turn:
 Answer these questions with a partner:
1. Which of the following things must involve a wave? You
may pick more than one. Explain each of your choices.
a) A bulldozer is moving the dirt for a highway
b) A person is talking to someone on a cell phone
c) An earthquake in the Pacific Ocean causes a house to
shake in Texas
d) A car is going 70 miles per hour on a highway
e) Two people stop to listen to a jet passing overhead
f) A doctor takes an X ray to check for broken bones
2. Draw a Transverse Wave. Label the a wavelength,
amplitude, crest and trough.

44. Anatomy of a Wave: