When I was studying electrical engineering in India in the 1980s, a professor asked our class: “Why do short- and medium-wave radios produce a crackling sound, or static, when a scooter goes past, regardless of the station you are listening to?” None of us knew the answer.
The professor was using the question to introduce a mathematical operation called a Fourier transform. Each time the spark plug in a scooter engine fires, it produces a short pulse of electromagnetic radiation. The Fourier transform reveals that, mathematically, this signal is a summation of thousands of sine and cosine waves. Whatever frequency our radios are tuned to, the pulse produced by the spark plug contains some energy at that frequency, which we hear as static. It was a proverbial ‘aha’ moment for many of us in the class.
Big Math by mathematicians Steven Strogatz and Alex Townsend contains many such aha moments. But the book is so much more. Strogatz and Townsend use the assuredness of mathematicians and the skill of storytellers to paint a vivid portrait of the variety of ways in which mathematics underpins almost every aspect of people’s lives.
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