The Brain Making Sense of an Orchestra

But our unconscious feats of unweaving and weaving are greater even than this. Think what is happening when you listen to a whole orchestra. Imagine that, superimposed on a hundred instruments, your neighbour in the concert is whispering learned music criticism in your ear, others are coughing and, lamentably, somebody behind you is rustling a chocolate wrapper. All these sounds, simultaneously, are vibrating your eardrum and they are summed into a single, very complicated wriggling wave of p...

 Fourier Transformations

So what was Fourier’s discovery, and why is it useful? Imagine playing a note on a piano. When you press the piano key, a hammer strikes a string that vibrates to and fro at a certain fixed rate (440 times a second for the A note). As the string vibrates, the air molecules around it bounce to and fro, creating a wave of jiggling air molecules that we call sound. If you could watch the air carry out this periodic dance, you’d discover a smooth, undulating, endlessly repeating curve that’...

 The Unique Properties of Ice

By the standard of other substances, the properties of ice are bizarre, yet ice is so perfectly suited to our purpose that if it didn't exist we should have to invent it. With few exceptions, the solid phase of matter is more dense than the liquid phase; water. alone among common substances, violates the rule. As water begins to cool, it first contracts and becomes more dense, in the typical way. But about four degrees above the freezing point, something peculiar happens. It ceases to contrac...