Lesson 4 of 7
Loudness and pitch
Goal: Link loudness to amplitude and pitch to frequency.
A bigger amplitude means a louder sound. A higher frequency means a higher pitch.
- An oscilloscope draws a sound as a wave. A microphone turns the sound into an electrical signal for it.
- Amplitude is the height of the wave, from the middle line to a peak. How loud a sound is can be measured in decibels (dB).
- Frequency is the number of waves each second. It is measured in hertz (Hz): 300 Hz means 300 waves every second.
- Wavelength is the distance from one peak of a wave to the next, as on the rope in lesson 1. In the same material, a higher frequency gives a shorter wavelength.
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Key words in this lesson
Wave A vibration that carries energy from place to place, but not matter
Amplitude The height of a wave, from its middle line to a peak
Wavelength The distance from one peak of a wave to the next
Frequency The number of waves each second, in hertz (Hz)
Pitch How high or low a sound is
Oscilloscope Shows a sound as a wave on a screen
Microphone Turns a sound wave into an electrical signal