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WAVESSound

Sound Video Links

Carol of the Bells –Explanation

Water Glasses

Auto-Tune

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Background Information

1. Longitudinal waves – move in and out by

compressing together

(Example: Sound Waves, slinky)

– Parts

• Compression – close together

• Rarefaction – far apart

Compression

Rarefaction

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What Is Sound?

Sound is vibrations.

MoleculesCOMPRESS and bump into each other!

(Without molecules or substance… there can be no sound!)

•Ex: Air particles compress and spread out until they meet your EAR!

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Sound Depends On:

1. A vibrating

source to make

waves

2. A medium to

carry the waves

3. A receiver to

detect them

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Can sound travel in empty space??

No! Sound can’t because there is no

medium or particles to BUMP into!

Light can travel through space because it is

like a particle

and a wave!

(Particle-wave duality

nature of light)

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Sound Vibrations

Back-and-forthPARALLEL

Sound travels away from the vibrating

object in radially all directions.

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Sound waves travel at all directions until it

reaches a surface where it is absorbed or

reflected.

This is how sound waves normally travel from one source.

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Sound waves from a tuning fork.

As the fork

vibrates it

causes

particles to

compress

and rarefact

(spread out)

What is the speed of

sound?

Through Air: 343 m/s @ 20º C

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Sound Travels faster through SOLIDS!!!

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Sound Travels at Different Speeds

Through Different Materials

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2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

20,000

WATER GRANITE

Meters per second

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Which Would Be the Best

Conductor of sound?

Solid?

Liquid?

Gas?

Solid – The

Bricks!

What mediums does sound

travel through?

1. SOLIDS – Fastest speed

2. LIQUIDS – Medium speed

3. GAS – Slowest speed

4. VACUUM – N/A (Doesn’t go

through it)

*This is key information to memorize14

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What happens when you

change the AMPLITUDE? Changes the VOLUME

(loudness)!

Amplitude (loudness) also

depends on:

Distance from the source.

The energy will decrease

and get softer as you move

away

Sound simulationVolume Control

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What happens when you

change the FREQUENCY?The Higher the Frequency the Higher the Pitch.

The Lower the Frequency the Lower the Pitch.

Depends on how fast the source of the sound is vibrating

Sound simulation

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Doppler Effect Sound is made

from a moving source

Sound travels away from or toward you.

Toward: higher pitch

Away: lower pitch

Ex: Car going by

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SONAR

To locate a target, a submarine uses SONAR (sound navigation and ranging).

SONAR emits pulses of sound waves that travel through the water, reflect off the target and return to the ship. By knowing the speed of sound in water and the time for the sound wave to travel to the target and back, the computers can quickly calculate distance between the submarine and the target

Whales, dolphins and bats use

the same technique for

locating prey (echolocation).

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High energy waves have…

1. High Amplitude

2. High Frequency

3. Short Wavelength