Sound

1. Chapter 12: Lesson 2:

2. What do you hear?

3. Is a type of energy we
hear.

4. Moves quickly back and
forth.

5. Compressio
n
Rarefaction

7. Outer ear
Middle ear
Inner ear
Ear
drum

8. Sound
Waves
Vibrations that
move through
matter

9. Direction of sound
Direction of energy

10. Sound waves moves in the
same direction the energy is
moving in.
Longitudina
l Waves

11. Waves that move in a
different direction.
Transverse
Waves

12. Sounds travel through 3
media.
- Sound travels through the solid the
fastest
(energy passed through closely packed particles)
- Sound travels through the gases the

13. What is an echo?
Echo are sound waves that are reflected
back.
(When the sound wave hits a flat, firm
surface)

15. How can echo or noise be
reduced?
By covering the room with soft, thick,
uneven material.
Wall
padding
Floor foam
Wood
panels
Wall art

16. How does covering rooms with the above
materials help?
When a sound wave hits the material the
sound is absorbed (changes to thermal energy).
Absorption:
Transfer of energy
when a wave
disappears into a
surface.

17. Frequency
The number of times an object vibrates
per second.
Unit:
Hertz (Hz).

18. Musical notes can be:
High notes Low notes
How high or low sound is.
Pitch

19. Low pitch
sounds has
lower
frequency.
High pitch
sounds has
higher
frequency.

20. Is there a difference between pitch and frequency?
YES!!!
Pitch is the way our ears hear sound.
(The way we hear sound is related to the
number of peaks BUT, they are not the same
thing)

21. How to change pitch?
High pitch
Short guitar
string
Vibrates fast
causing high pitch

22. Low pitch
Long guitar
string
Vibrates slowly
causing low pitch

23. If you are standing still the sound
waves will sound normal

24. If the source of sound is moving
towards you, you will hear more
vibrations.
So the
sound you
are hearing
becomes
high
pitched.

25. If the source of sound is moving away
from you, you will hear less vibrations.
So the sound you are hearing
becomes low pitched.

26. When sound frequency changes due to
moving towards or away from the
sound.
The Doppler
effect.

28. When you are TALKING the sound
waves will look like this
When you are SCREAMING the sound
waves will look like this
When you are WHISPERING the sound
waves will look like this

29. Amplitude
How dense is the air during
compressions and rarefactions.
Units:
Decibels (dB)

30. Humans hearing range.