1. Pitch & Volume
D. Crowley, 2008

2. Pitch & Volume
To know how the pitch and the volume of a sound affect the sound wave it produces

3. Speed Of Sound
In which medium will sound travel fastest (air; water; brick or iron)?
Why do you think sound travels faster in some mediums, and slower in others?

4. Speed Of Sound
Sound waves disperse less energy when moving through a medium of greater density
In other words, the denser the medium the faster the sound passes through it (generally)
Sound travels through the iron much more quickly than through air, as the iron is so much more dense (particles are much closer together)

5. Viewing Sound
Sound can be studies using a signal generator to produce different types of sound, a loudspeaker so we can hear the sound, and a oscilloscope which lets us ‘see’ the sound
Oscilloscope (turns the sound into a visual signal)
Loudspeaker (allows us to hear the sound)
Signal generator (produces different sounds)

6. Sound Waves
Listen to the different sounds produced as the frequency changes – listen carefully to where your hearing begins / ends
As you listen, view the oscilloscope to see how the waves are changing

7. Amplitude A sound can be quiet or loud
Amplitude is a measure of how loud a sound is (how much energy the wave carries) – a big amplitude means a loud sound
A quiet sound on an oscilloscope (short wave height)
A loud sound on an oscilloscope (tall wave height)

8. Amplitude
Which trace represents the greatest amplitude (loudest sound)? A B
Sound A has the largest amplitude (tallest waves)
so is the louder of the two sounds

9. Pitch & Wavelength
A sound can be low (mooing cow) or high (squeaking mouse)
Pitch depends on the frequency of the waves (number of complete vibrations each second, measured in hertz (Hz))
A low pitch sound on an oscilloscope (few wave per second)
* long wavelength
A high pitch sound on an oscilloscope (many waves per second)
* short wavelength

10. Pitch & Wavelength
Which trace represents the highest pitch, like that of a squeaking mouse (shortest wavelength)? A B
Sound B has the most waves across it (short wavelength for each wave) meaning it has a higher frequency = higher pitch

11. Wave Variations

12. Wave Envelopes
Sounds can vary greatly in their amplitude (loudness) and frequency (pitch)
Listen and visualise the sounds and their wave envelopes