1. 06/12/2018
Sound and Hearing

2. Speed of sound
06/12/2018
The speed of sound in air is around 330 m/s. What happens when sound travels through different materials?
Speed of sound
(in m/s)
Material
Conclusion – the denser the material, the faster sound travels through it

3. Making Sounds A sound is made when an object or material VIBRATES.
06/12/2018
A 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

4. Using an oscilloscope 1) Quiet sound, low frequency:
06/12/2018
1) Quiet sound, low frequency:
2) Quiet sound, high frequency:
3) Loud sound, low frequency:
4) Loud sound, high frequency:

5. How sound travels…
06/12/2018
As we know, sound waves are formed when something vibrates. But how does the sound reach our ears?
Air molecules
2) The vibrations pass through air by making air molecules vibrate
3) These vibrations are picked up by the ear
1) An object makes a sound by vibrating

6. How does the ear work?
06/12/2018
1) Sound waves are “funnelled” into the ear by the pinna
5) The electrical signals are then sent to the brain
3) These vibrations make the ear bones vibrate
4) These vibrations are turned into electrical signals in the cochlea
2) These vibrations make the ear drum vibrate