Sound and Hearing

Speed of soundThe speed of sound in air is around 330 m/s. What happens when sound travels through different materials?

0

1000

2000

3000

4000

5000

Air Water Brick I ron Material

Speed of

sound

(in m/s)

Conclusion – the denser the material, the faster sound travels through it

Making SoundsA sound is made when an object or material

VIBRATES.Take, for example, a guitar.

To make a sound with a guitar a string has to vibrate. We can raise the pitch of the sound a guitar makes by doing three things:

1) _________ the length of the string

2) _________ the string

3) Using a _________ string

We can make the sound louder by ________ the string harder

Words – tightening, thinner, increasing, plucking

Using an oscilloscope

1) Quiet sound, low frequency:

2) Quiet sound, high frequency:

3) Loud sound, low frequency:

4) Loud sound, high frequency:

How sound travels…As we know, sound waves are formed when something vibrates. But how does the sound reach our ears?

1) An object makes a sound by vibrating

2) The vibrations pass through air by making air molecules vibrate

3) These vibrations are picked up by the ear

Air molecules

How does the ear work?1) Sound waves are “funnelled” into the ear by the pinna

4) These vibrations are turned into electrical signals in the cochlea

2) These vibrations make the ear drum vibrate

3) These vibrations make the ear bones vibrate

5) The electrical signals are then sent to the brain