Visualizing Sound Waves with an Oscilloscope

An oscilloscope connected to a signal generator and speaker allows sound waves to be seen as patterns on a screen. By adjusting frequency and amplitude, students can explore how pitch and loudness correspond to wave characteristics.

1. Connect a signal generator to both a speaker and an oscilloscope.
2. Adjust the oscilloscope’s timebase so the wave is clearly visible on the screen.
3. Produce a low-frequency sound and observe its long wavelength on the oscilloscope.
4. Increase the frequency and note how the wavelength shortens and pitch rises.
5. Adjust the amplitude on the signal generator and observe the taller or shorter waveforms, while noting that pitch does not change.
6. Compare different frequency ranges to illustrate the upper and lower limits of human hearing.
7. Discuss how sound properties are represented visually: frequency as spacing of waves, amplitude as wave height.

Visualising sound waves with an oscilloscope - CLEAPSS:

Sound Waves with an Oscilloscope - Teacher Demos - Mr clark:

• Use different waveforms (sine, square, triangle) and compare how they sound and appear.
• Record a voice or musical instrument with a microphone connected to the oscilloscope.
• Explore very low frequencies where the sound is felt as vibration rather than heard.

• Keep speaker volume at safe levels to protect hearing.
• Avoid prolonged exposure to high frequencies, which may cause discomfort or damage.
• Handle oscilloscope and signal generator carefully, following lab electrical safety rules.

• How does the oscilloscope trace change as frequency increases? (The waves get closer together, representing higher pitch.)
• How is amplitude shown on the oscilloscope? (By the height of the wave.)
• Why does amplitude affect volume but not pitch? (Amplitude changes wave energy, while pitch depends only on frequency.)
• What frequencies can humans typically hear, and how does this change with age? (Roughly 20 Hz to 20 kHz; the upper range decreases with age.)