Sound and Hearing

1. Sound and Hearing W Richards The Weald School

2. Speed of sound 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. 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: 2) Quiet sound, high frequency: 3) Loud sound, low frequency: 4) Loud sound, high frequency:

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

6. How does the ear work? 1) Sound waves are “funnelled” into the ear by the pinna 5) The electrical signals are then sent to the brain 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