1. Integrated Science
Unit 4, Chapter 13

2. Unit Four: Sound and Waves
Chapter 13 Sound and Music
13.1 Sound
13.2 Properties of Sound
13.3 Music

3. Chapter 13 Learning Goals
Learn how we hear sound.
Learn how your brain interprets sound to understand words and music.
Learn what kinds of sounds we can hear, and what kinds we cannot hear.
Learn what a sound wave is and how it travels.
Learn how the loudness of sound is measured.
Learn the basics of acoustics as applied to the design of buildings and musical instruments.
Learn to read a sonogram and how a computer recognizes spoken words.
Learn what supersonic means.
Learn why a musical scale sounds good, or why it sounds bad.
Learn how we tell voices and instruments apart from each other.

4. Chapter 13 Vocabulary Terms
acoustics
beat/beats
consonance
cochlea
dissonance
decibel
harmonics
harmony
musical scale
pitch
pressure
reverberation
rhythm
sonogram
sound
supersonic
ultrasound
white noise

5. 13.1 Sound What is sound and how do we hear it? Key Question:
*Read text section 13.1
AFTER Investigation 13.1

6. 13.1 Sound
Sound has a frequency that we hear as higher or lower pitch.
Sound has a wavelength that we can construct experiments to show.
The speed of sound is frequency times wavelength.
Resonance happens with sound.
Sound can be reflected, refracted, and absorbed.
Sound shows evidence of interference and diffraction.

7. 13.1 Sound
The eardrum vibrates in response to sound waves in the ear canal.
The three delicate bones of the inner ear transmit the vibration of the eardrum to the side of the cochlea.
The fluid in the spiral of the cochlea vibrates and creates waves that travel up the spiral.

8. 13.1 Sound
The nerves near the beginning see a relatively large channel and respond to longer wavelength, low frequency sound.
The nerves at the small end of the channel respond to shorter wavelength, higher-frequency sound.

9. 13.1 The range of human hearing

10. 13.2 Properties of Sound
Pressure is a measure of the force of molecules being exerted on their surroundings.

11. 13.2 Properties of Sound
More molecules per unit volume makes pressure go up.
Fewer molecules per unit volume makes the pressure go down.

12. 13.2 What sound might look like:
If you could see the atoms, the difference between high and low pressure is not as great. Here, it is exaggerated.

13. 13.2 Loudness
Logarithmic scale
Linear scale
Decibels (dB)
Amplitude 1 20 10 40
100 60
1,000 80
10,000
100,000
120
1,000,000
Every increase of 20 dB, means the pressure wave is 10 times greater in amplitude.

14. Common Sounds and their Loudness

15. 13.2 The Frequency of Sound
We hear frequencies of sound as having different pitch.
Our ears are more sensitive to sounds between 100 and 2,000 Hz.
Most frequencies that make up speech are also between 100 and 2,000 Hz.

16. 13.2 Complex Sound

17. 13.2 The Wavelength of Sound

18. 13.2 Properties of Sound Does sound behave like other waves?
Key Question:
Does sound behave like other waves?
*Read text section 13.2 BEFORE Investigation 13.2

19. 13.3 Music What is music and how do we make music? Key Question:
*Read text section 13.3
AFTER Investigation 13.3

20. 13.3 Music: Pitch and Rhythm
The pitch of a sound is how high or low we HEAR a frequency. The way we hear pitch can be affected by the sounds we heard before and after.
Rhythm is a regular time pattern in a sound.

23. 13.3 Beats
Beats occur when two frequencies are close, but not exactly the same.

24. 13.3 Consonance and Dissonance
Consonance is when we hear more than one frequency and the combination sounds good.
When the combination is unsettling or unpleasant, dissonance occurs.

25. 13.3 Harmonics and "the color of sound"
The same note can sound different when played on different instruments..
Instruments make mixtures of different frequencies.
Compare these voices saying hello: