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Why a CD takes 44,100 snapshots a second: Nyquist and the tone that folds back A CD stores music as 44,100 numbers a second, with nothing in between. Sample more than twice as fast as the highest pitch and the wave can be rebuilt exactly… Music & Sound4 min read2 Nov How babies find words in a stream of sound: transitional probabilities Babies hear speech as one unbroken smear, with no gaps between words, yet somehow they start picking out words long before they can say one. One clue sits in… Language4 min read30 Oct Why dragging a bow makes a steady note: stick-slip and Helmholtz's travelling kink A bow moves at a steady speed, yet the string under it vibrates in an exact rhythm hundreds of times a second. The secret is stick-slip: rosin grips the… Music & Sound4 min read30 Oct How two royal names in rings cracked hieroglyphs: Ptolemy, Cleopatra and the Rosetta Stone In 1799 a slab was dug up near Rosetta carrying one decree in three scripts, and nobody could read two of them. The first foothold was tiny: royal names sealed… History4 min read28 Oct Why two steady rhythms can fight and still groove: the hidden grid of 3 against 2 Tap a steady beat with one hand and three evenly spaced taps in the same time with the other, and you get a 3:2 polyrhythm: two perfectly regular clocks that… Music & Sound4 min read27 Oct Why random dice rolls draw a perfect fractal: the chaos game and the Sierpiński triangle Pick three dots, then keep jumping halfway towards a randomly chosen one. It sounds like it should leave a grey smudge, but after a few thousand jumps a… Maths3 min read24 Oct Why you hear a note that isn't there: the missing fundamental Play only 220, 330 and 440 hertz and most people hear a note at 110 hertz — a frequency that is not in the sound at all. This is the missing fundamental: the… Music & Sound5 min read23 Oct Why a siren drops in pitch as it passes: the Doppler effect An ambulance siren sounds high as it comes at you and drops the moment it passes, yet the driver hears one steady note. The trick is in how crests per second… Physics3 min read21 Oct Why two almost-equal notes make a wobble: beats and the piano tuner's trick Play two almost-equal notes together and you hear one pitch that swells and fades. Those swells are beats, and their rate is simply the difference in… Music & Sound4 min read20 Oct Why Latin p became English f: Grimm's law and the sound-shift chain Latin says pes, English says foot. Latin tres, English three. Latin cornu, English horn. The swap is not random: when the Germanic languages split off, their… Language5 min read16 Oct Why a piano can never be perfectly in tune: twelve fifths overshoot seven octaves Climb twelve perfect fifths and you should land back on your starting note, seven octaves up. You don't: you overshoot by 23.46 cents, nearly a quarter of a… Music & Sound4 min read16 Oct Why a boat's wake is always a 39° V: Kelvin's wedge Behind every boat spreads a V of ripples, and it is always about 39° wide, whether the boat crawls or speeds. Lord Kelvin worked out why in 1887: only waves… Physics4 min read14 Oct