An oscilloscope trace shows a sound wave as a graph. The oscilloscope screen shows voltage (related to pressure/displacement) on the y-axis and time on the x-axis.
- The time base setting tells you the time represented by one horizontal division (e.g., 1 ms/div)
- Count the number of divisions for one complete wave cycle → this gives the period T
- Calculate frequency from f = 1/T
- The amplitude is the height from the centre line to a crest (read in divisions × voltage/div)
Quick Check: On an oscilloscope trace, you increase the amplitude of the sound but keep the pitch the same. Describe what you would observe.
The waves would appear taller (greater maximum displacement from the centre line) but the spacing between waves (wavelength) would remain the same — the frequency is unchanged so the number of waves across the screen stays the same.
This key facts covers Interpreting Oscilloscope Traces within Sound Waves for GCSE Physics. Revise Sound Waves in Waves for GCSE Physics with 16 exam-style questions and 15 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 10 of 13 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Sound Waves
What type of wave is sound?
Describe how a sound wave is produced and how energy is transferred by a longitudinal wave.