1. Sound Waves (Copy all red words into your notebook)
Photos, sounds, and clipart were obtained from Microsoft’s Office products, unless noted on the slide.

2. Sound Waves Sound travels in waves.
3.9 The student will recognize that sound is a form of energy. [P8C2]

3. This is Alexander Graham Bell’s sketch of how a telephone works.
This sketch came from the Library of Congress “American Memory Project.”
We have requested permission to use several other historical photos. As soon as permissions are granted, I will post them. Loretta 

4. Sound Waves Sound travels in waves. Sound travels through a medium.
What happens when this worker bangs on the steel?
3.3 The student will describe how waves move at different speeds in different materials. [P8C2]

5. Sound Waves Sound travels in waves. Sound travels through a medium.
What is the medium for these sound waves?
3.3 The student will describe how waves move at different speeds in different materials. [P8C2]

6. Sound Waves Sound travels in waves. Sound travels through a medium.
Describe sounds under water.
3.3 The student will describe how waves move at different speeds in different materials. [P8C2]

7. Sound Waves Sound travels in waves. Sound travels through a medium.
3.3 The student will describe how waves move at different speeds in different materials. [P8C2]
A medium can be solid, liquid, or gas.
Sound waves travel through all of these.

8. Sound Waves Sound travels in waves. Sound travels through a medium.
3.3 The student will describe how waves move at different speeds in different materials. [P8C2]
In dry air, sound travels at about 340 m/s.
In steel, sound travels at about 5960 m/s.
In water, sound travels at about 1482 ms/s.
Students may need to understand that some media, such as a desktop, contain solids and a lot of air.
How could you design an investigation to find out which medium sound will travel through the fastest?

9. Sound Waves Sound travels in waves. Sound travels through a medium.
Sound waves cannot travel without a medium.
3.3 The student will describe how waves move at different speeds in different materials. [P8C2]

10. Sound Waves Sound travels in waves. Sound travels through a medium.
Put your fingers gently on your throat and hum.
Describe what you felt.
Tap your desk.
What is the sound traveling through? (Hint: Don’t forget how the sound gets to your ears.)
3.3 The student will describe how waves move at different speeds in different materials. [P8C2]

11. Sound Possibilities
What would you predict would happen when a sound wave went through air and hit water?
How about when it traveled from steel into air?
3.3 The student will describe how waves move at different speeds in different materials. [P8C2]

12. Sound Possibilities When a sound wave hits a new medium:
Some or all of it could be absorbed.
What happens when you yell into a pillow?
3.3 The student will describe how waves move at different speeds in different materials. [P8C2]
3.4 The student will differentiate among reflection, refraction, and absorption of waves. [P8C2]

13. Sound Possibilities What is an echo?
When a sound wave hits a new medium:
Some or all of it could be absorbed.
Some or all of it could be reflected.
What is an echo?
3.3 The student will describe how waves move at different speeds in different materials. [P8C2]
3.4 The student will differentiate among reflection, refraction, and absorption of waves. [P8C2]

14. Sound Possibilities Underwater, do you hear someone outside?
When a sound wave hits a new medium:
Some or all of it could be absorbed.
Some or all of it could be reflected.
Some or all of it could be refracted or bent.
3.3 The student will describe how waves move at different speeds in different materials. [P8C2]
3.4 The student will differentiate among reflection, refraction, and absorption of waves. [P8C2]
Underwater, do you hear someone outside?

15. Parts of a Wave
D = one full wave
= one wavelength
= one period D A C
C = Amplitude
A = Crest B
3.1 The student will investigate wavelength, frequency, amplitude, and velocity as properties of waves. [P8C1, P8C2]
Review the parts of a wave.
B = Trough
Frequency is how many full waves pass a point in one second (Hertz).

16. Sound Frequency Frequency is about how many waves go past a point.
More waves are going past here
Higher Frequency
than here.
Waves
3.1 The student will investigate wavelength, frequency, amplitude, and velocity as properties of waves. [P8C1, P8C2]
Lower Frequency

17. Sound Frequency Wave frequency is related to pitch.
A high frequency is a high pitch.
Waves
A low frequency is a low pitch.
3.1 The student will investigate wavelength, frequency, amplitude, and velocity as properties of waves. [P8C1, P8C2]
Waves

18. Sound Amplitude Amplitude is how tall the wave is.
Wave amplitude is related to volume (loud or soft).
A low amplitude wave has a soft volume.
Amplitude
3.1 The student will investigate wavelength, frequency, amplitude, and velocity as properties of waves. [P8C1, P8C2]

19. Sound Amplitude Amplitude is how tall the wave is.
Wave amplitude is related to volume (loud or soft).
A low amplitude wave has a soft volume.
Amplitude
A high amplitude wave has a loud volume.
3.1 The student will investigate wavelength, frequency, amplitude, and velocity as properties of waves. [P8C1, P8C2]
Amplitude

20. Sound Frequency Give an example of a high frequency sound.
Give an example of a low frequency sound.
3.1 The student will investigate wavelength, frequency, amplitude, and velocity as properties of waves. [P8C1, P8C2]
Good place to “pose, pause, pounce, and bounce.”

21. Echolocation
Echolocation- sound waves reflect back and identify an objects location
Bats use echolocation.
3.1 The student will investigate wavelength, frequency, amplitude, and velocity as properties of waves. [P8C1, P8C2]
3.2 The student will describe how wavelike disturbances spread uniformly away from the source. [P8C2]
3.4 The student will differentiate among reflection, refraction, and absorption of waves. [P8C2]
Use the reading about echolocation in Chapter 3 of their textbook.
Echolocation in dolphins:
All kinds of info about bats:
Echolocation in various marine animals:

22. How do you hear sounds? Sound waves go into your ear.
The energy moves the small bones inside your ear.
The nerves send a message to your brain.
3.2 The student will describe how wavelike disturbances spread uniformly away from the source. [P8C2]
3.4 The student will differentiate among reflection, refraction, and absorption of waves. [P8C2]

23. How do you hear sounds? This diagram came from www.nasa.gov
3.2 The student will describe how wavelike disturbances spread uniformly away from the source. [P8C2]
3.4 The student will differentiate among reflection, refraction, and absorption of waves. [P8C2]
Help students understand that the sound waves are mechanical energy.
Click on arrows to make them move.
This diagram came from