An oscilloscope is a machine that shows the wave shape of an electrical signal. When connected to a microphone they can show the wave shapes of sounds. These diagrams show oscilloscope traces of three sounds:
The frequency of a sound is the number of oscillations (waves) per second and is measured in hertz (Hz). It can be calculated by:
The time period is the time taken to complete one oscillation and is measured in seconds. So if the time period of a sound wave is 0.01 seconds, then the frequency is calculated as:
frequency = 1 ÷ 0.01
= 100 hertz
This would make a low pitched sound (low frequency) as this is towards the bottom of our audible range.