Art or math?

What is this? Modern art? A lost work by Jackson Pollock?

sine-wavesActually, no.

In my precalculus class this morning, we were using the Oscilloscope app on the iPad to produce real-time graphs of various musical tones. Students brought instruments into class — a flute, a trumpet, a couple of violins, a cello, a string bass, and cymbals — so that we could hear the  different sounds and look at the sine waves they produce. The class already knew that the A above Middle C produces a 440Hz sound, so they knew that its period was 1/440 of a second, but then why do all these instruments sound so different? One junior went up to the whiteboard and traced out each curve after we froze it, producing this work of art.

Only the flute, by the way, produced something that looked almost like a perfect sine wave. (It couldn’t be perfect because of ambient noise, but it was very close. If we had been in a sound studio, we could have avoided the noise.)



Categories: Math