How good is Luke Quartermaine at hitting an F on the first note playing his trumpet? He was aiming for 349.2Hz … take a look at the oscilloscope screen to see how he did!
In Physics, Year 10 have studied the topic of waves, including an understanding of the frequency of sound vibrations. The oscilloscope trace in yellow shows the shape of the waveform produced by Luke as he played the note.
This complex waveform is more than just an F, since it also has many harmonics at integer (whole number) multiples of the first harmonic. Look at the red trace at the bottom, which displays the frequency spectrum of the sound. You can see how the amplitudes of the harmonics compare with each other (the first eight show clearly as the eight peaks on the left).
Your inner ear has many tiny cells with hairs that vibrate in a fluid, each one responding to a different frequency, just like the red trace on the oscilloscope. The signals sent to the auditory cortex of your brain lead to a perception not of eight sounds, but of a single sound with the distinctive tonal characteristics of Luke’s trumpet playing! The many harmonics also change your perception of the sound, making it appear a lot louder than a simple sine wave of the same amplitude.
Other very different sounds were also analysed, with Vincent Lagos Colombel on the violin and Paddy Watt on drums!