_science.science.sound.elementary__sound.ppt

elementary category
sounds...science...science

1. Sound
Chapter 24

2. 24-1 What is Sound?
I can explain how sound waves are produced.
I can describe how sound waves are
transmitted.
I can compare the phases of matter as to
their ability to transmit sound
I can describe how the speed of sound is
affected by the density of the medium through
which it travels.

3. How sounds are made…
Sound is produced when matter vibrates.
As an object vibrates, it gives energyto the
particles of matter around it.
Sound is a longitudinalwave.
It moves with a series of compressionand
rarefactions.

4. Sound Waves
Molecules in the air vibrateabout some average
position creating the compressions and rarefactions.
We call the frequency of sound the pitch.

5. Anything that vibrates produces sound.
When you speak, your vocal cordsvibrate.
Particles of air simply move back and forth.
A radio would NOTwork in outer space
because there is not any mediumfor sound to
travel through.
“If a tree falls in the forest and no one is
present to hear it, is there a sound?”

6. Speed of Sound
Determined by the temperature, elasticity,
and density of the medium.
Temperature
Sound travels slowerin lower temperature
Sound travels fasterin higher temperature
Average speed of sound in air = 340 m/s

7. Medium Speed (m/s)
Air 343
Helium 972
Water 1500
Steel 5600

8. Elasticity & Density
Sound can travel through anymedium.
Greatest speed in solids, slowest speed in
gases.
Fastest in more elasticmediums, solids are
more elastic.
In materials of the same phase, the more
densethe slower the waves travel.

9. 24-1 What is Sound?
I can explain how sound waves are produced.
I can describe how sound waves are
transmitted.
I can compare the phases of matter as to
their ability to transmit sound
I can describe how the speed of sound is
affected by the density of the medium through
which it travels.

10. Book Work
24-1 Section Review
Page 618
#1-4
Section 24-1 Worksheet

11. 24-2 Properties of Sound
I can describe the properties of sound waves.
I can explain how frequency and pitch are
related.
I can describe the Doppler effect.

12. Frequency & Pitch
Sounds can be described by high or low
pitches.
Pitch depends on how fastthe particles of
the medium vibrate.
Pitch is the number of waves in a given
amount of time, also known frequency.
Meaning the pitch depends on the frequency.

13. Pitch
A measure of howhigh or low a sound is
Pitch depends on thefrequencyof a sound wave
For example,
-Low pitch
-Low frequency
-Longer wavelength
-High pitch
-High frequency
-Shorter wavelength

14. Doppler Effect
Police car speeding by:
Higherpitch as approached, lower pitch as
moving away.
Change in pitch is referred to as the Doppler
effect.
Occurs whenever there is motionbetween the
source of a sound and its receiver.
Source or receivermust be in motion.

15. Doppler Effect
Police car moving towards you, pushing waves
togethercausing:
Shorter wavelengths, higher freq., higher pitch.
Police car moving away from you, spreading
waves out:
Longer wavelengths, lower freq., lower pitch

16. Loudness
Chart
Loudnessis
related to the
amount of
energy
carried by a
wave.

17. 24-2 Properties of Sound
I can describe the properties of sound waves.
I can explain how frequency and pitch are
related.
I can describe the Doppler effect.

18. Terms to Know
Pitch
Doppler Effect
Book Work
24-2 Section Review
•Page 623
•#1-4
•Name that Sound
Worksheet

19. 24-6 How You Hear
I can identify the parts that make up the ear.
I can explain how vibrations are converted
into electrical signals.

20. For Sound to be heard…
You need 3 things:
1. a sourcethat produces the sound
2. a mediumto transmit the sound
3. an organof the body that detects the sound
Sound enters the outer ear, vibrates
eardrum, enters middle ear and vibrates
liquid-filled inner ear.

21. Human Ear

22. Outer Ear
The outer ear acts as funnelfor the waves.
The waves travel through the ear canaland hit
the lightly stretched membrane called the
eardrumcausing it to vibrate.
The vibrations then
enter the middleear.

23. Middle Ear
The middle ear contains the 3 smallest
bones in the body.
hammer, anvil,stirrup
The vibrations travel
through the 3 bones
and are transmitted to
a liquid-filledinner ear.

24. Inner Ear
The inner ear contains
the cochlea.
Cochlea is snailshaped
Contains liquid and
hundreds of cell
attached to nerve fibers
The nerve fibers form
one larger nerve that
travelsto the brain
where they are
interpreted as sound

25. Human Ear

26. 24-6 How You Hear
I can identify the parts that make up the ear.
I can explain how vibrations are converted
into electrical signals.

27. Chapter Review Pg 638
Multiple Choice
#2-5, 9-10
True or False
#1-4, 6
Concept Mastery
#1-4
After Chapter Review is
turned in…
-Study vocabulary words