sound

What are sound waves?

Vibrations that travel through a medium as longitudinal waves

What type of wave is sound?

Longitudinal wave

What is a medium?

A substance that sound travels through (solid, liquid, or gas)

Why can’t sound travel through a vacuum?

There are no particles to vibrate

What is a compression?

Region where particles are close together

What is a rarefaction?

Region where particles are spread out

What does amplitude measure?

Loudness of a sound

What happens when amplitude increases?

The sound becomes louder

What does frequency measure?

Pitch of a sound

What happens when frequency increases?

The pitch becomes higher

What unit is frequency measured in?

Hertz (Hz)

What does an oscilloscope show?

A visual display of a sound wave

On an oscilloscope, what shows loudness?

The height of the wave (amplitude)

On an oscilloscope, what shows pitch?

The spacing of the wave (frequency)

What part of the ear vibrates when sound enters?

The eardrum

What happens after the eardrum vibrates?

Vibrations are turned into electrical signals sent to the brain

How do sound waves move through air?

By particles vibrating back and forth

Do sound waves transfer matter?

No, they transfer energy only

How does sound travel?

• an object makes a sound by vibration

• the vibrations pass through the air by making air molecules vibrate

• these vibrations are picked up by the ear

• the ear then send a message to the brain

1. vibrating ear particles are funnelled into ear by the pinna (ear flap)

2. vibrating the particles make the eardrum vibrate

3. the eardrum makes the small bones vibrate which magnifies the vibration

4. the bones make the fluid in the cochlea move which bends the tiny hairs inside

5. the hairs are connected to the nerve cell which send electrical signals to the along the auditory nerve to the brain