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Sound Energy

Sound Energy

• Sound is formed by vibrations.

• Vibrations: the quick back and forth motion of atoms against each other

Sound Waves• Sound vibrations form waves.

• Sound moves in waves.

• Sound waves MUST have matter to move through (a solid, liquid or gas).

• Sound waves can move through all forms of matter. Sometimes matter is called mediums.

How we hear soundHumans and animals use eardrums to hear

sound. The eardrum vibrates when vibrating air passes by it.

A sound wave

Your computer can display sound waves during a song.

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Light can move through outer space.

Can sound move through space?(hint: Sound must have some sort of medium or

form of matter to move through or it can’t move.)

Will you see 2 asteroids crash into each other? Will you hear 2 asteroids crash into each other?

How does sound move?

• Sound waves move through matter by making the atoms (particles) bump against each other and making the atoms vibrate.

• Without atoms, sound waves can not move or vibrate.

Solids, Liquids and Gases

• Solids: – Sound moves very fast

• Liquids: – Sound moves a little slower

• Gases: – Sound moves the slowest

• Solids: sound waves move fast– Tap on a table with your ear against the table. You

can hear the sound pretty quick.

• Liquids: sound waves move a little slower– Have you ever yelled underwater? You can hear

the sound underwater, but the sound moves slowly through water.

• Gas: sound waves move very slow– Although you seem to hear sounds pretty quickly

through air, it really is the slowest medium that sound moves through.

Crank it up!Light travels faster than sound.

Which comes first???:

- you seeing the jet or the sound of the jet engine?

Ripples and Vibrations

Have you ever thrown a rock into a lake? Did you notice the water make ripples?

That is exactly how sound waves look when they are moving through a medium.

or like the center of an earthquake

The sound waves spread out from the center (the source).

Surprise!

Sound waves never disappear.

They just spread out further and further !!

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What is the difference between light waves and sound waves?

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What is similar between light waves and sound waves?

Sound Conductors

Conductors: Allow sound to travel.

They are good “carriers”.

They carry the sound along.

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What do you think are good conductors of sound?

Clue:Make Mrs. Harada proud…..

Good sound conductors…

If you can hit something and it makes a sound, it is a good conductor.

»wood

»metals

»plastic

Sound Insulators

Insulators: Do not allow sound to travel through them. They do not

carry the sound along.

Insulators usually have lots of air pockets in it.

Remember: sound travels best through solids with particles close together.

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What do you think are good insulators of sound ?

Clue:

Think about what you would use to stop sound or make something quieter.

Good Sound Insulators…

If you hit something and it does NOT make loud sounds, it is a good insulator.

• Cloth

• Foam

• Some plastics

Echo

An echo is when sound waves bounce off something and are sent back.

This is how “sonar” works to find submarines.

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When will you hear an echo?

• Open field ?

• Mountains ?

• Cave ?

• Our classroom?

• Valley?

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Now that you know light and sound,

explain a thunderstorm.

The End