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Why the most common words are the shortest: Zipf's two laws of language Count the words in almost any long text and a strange pattern appears: the most common word turns up about twice as often as the second, three times as often… Language5 min read26 Sep Why a piano has 12 notes: the circle of fifths that never quite closes Stack pure 3:2 fifths, the most consonant interval after the octave, and you'd expect to eventually land back on your starting note. You never do. After twelve… Music & Sound5 min read26 Sep How computers fake grey using only black and white dots Old Mac screens, cheap printers and some modern games can only show two colours: black and white. Yet they still draw soft shadows and smooth skies. The trick… Computing5 min read26 Sep Why English spelling doesn't match how words sound Around 1400, English spelling roughly matched speech. Bite sounded close to "beet", meet roughly like "mate", and house like "hoose". Then, over about three… Language5 min read26 Sep How a computer adds 7 + 1 using nothing but switches A computer chip has no idea what numbers are. It only has switches: billions of transistors that are either on or off. Yet wire a few of those switches into… Computing5 min read26 Sep Why popcorn pops, and why some kernels never do A popcorn kernel is a tiny, sealed pressure vessel. Its hard shell traps water inside the starchy core until heat turns that water to steam, and pressure… Food Science5 min read26 Sep Why we only ever see one side of the Moon The Moon always shows us the same face, so it's easy to assume it doesn't spin. It does. It turns exactly once for every orbit, about every 27.3 days, so the… Earth & Space6 min read26 Sep Why you can't tickle yourself (and how a robot can fix that) Every time you move, your brain keeps a copy of the command and uses it to predict what you're about to feel. Sensations that match the prediction get turned… Mind6 min read26 Sep Why shared fish, fields and water get used up, and how some places don't When something is shared and nobody controls it, taking a bit more is always worth it for you. You keep the whole gain; the damage is split among everyone… Economics6 min read26 Sep How sailors found longitude before satellites: a race against the clock Latitude is easy: measure the height of the Sun or the Pole Star. Longitude is hard, because the Earth turns one degree every four minutes. To know how far… History6 min read26 Sep Ten thousand fireflies, no conductor Once a year in the Great Smoky Mountains, thousands of fireflies flash on and off together, down to a fraction of a second, for hours. No leader calls the… Biology6 min read26 Sep Why a rainbow is always a circle 42° around your shadow Every rainbow is part of a circle centred on the shadow of your head, with its red edge about 42° away. That number comes from inside a single raindrop… Physics5 min read26 Sep