2.2 - Sound Waves

What are sound waves?

longitudinal waves that cause particles to vibrate parallel to the direction of wave travel

What can vibrations travel through?

solid, liquids and gases

What does the speed of sound depend on?

the medium through which it is travelling

What is the speed of sound travelling through air?

330 metres per second

What is the symbol for metres per second?

m/s

Can sound travel through a vacuum?

No hecause there are no particles to carry the vibrations

How does the human ear detect sound?

1. sound waves enter the ear canal and cause the eardrum to vibrate

2. three small bones transmit these vibrations to the cochlea

3. this produces electrical signals which ass through the auditory nerve to the brain, where they are interpreted as sound

What is the frequency of a sound wave related to?

the pitch heard

What noise do high frequency sound waves make?

a high pitched noise

What noise do low frequency sound waves make?

a low pitched noise

What is the amplitude of a sound wave related to?

the volume of sound

What volume are high frequency sound waves?

loud

What volume are low frequency sound waves?

quiet

What is an oscilloscope?

device used to record signals that change regularly such as sound or other vibrations

What sounds to oscillliscope traces show?

• quiet, low pitched sound

• loud, low pitched sound

• loud, high pitched sound

Why can human only hear certain frequencies?

the cochlea is only stimulated by a limited range of frequencies, so humans can only hear cetain frequencies

What is the range of normal human hearing?

20 - 20,000 Hz