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Why English plurals say s, z or iz: the wug test Say 'cats' and 'dogs' out loud and listen to the last sound. One is a hiss, the other a buzz, and 'buses' adds a whole extra syllable. English spells all three… Language4 min read13 Oct Why a flute and a clarinet sound different on the same note: harmonics and timbre Play the same note on a flute and a clarinet, at the same pitch and loudness, and you can still tell them apart at once. That difference is called timbre, and… Music & Sound4 min read13 Oct Why common letters get short codes in a ZIP file: Huffman coding ASCII spends 8 bits on every letter, whether it is a common e or a rare z. In 1951 a graduate student, David Huffman, found a way to give frequent symbols… Computing4 min read12 Oct Why a blink of blank screen hides big changes: change blindness Show someone two nearly identical pictures with a blink of blank screen between them, and a large change can stay hidden for many seconds. This is change… Mind4 min read12 Oct Why a stone arch stands without glue: Hooke's upside-down rope A stone arch has no glue, yet it stands for centuries because every block is only ever squeezed. In 1675 Robert Hooke hid the secret in an anagram: as a… Engineering5 min read12 Oct Why good used cars vanish from the market: Akerlof's lemons Why can a market of willing buyers and sellers fall apart? In 1970 the economist George Akerlof showed that when only the seller knows a used car's quality… Economics4 min read12 Oct Why oil and water mix in mayonnaise: an egg yolk coats every droplet Oil and water refuse to mix, yet mayonnaise is about two-thirds to four-fifths oil and holds its shape on a spoon. One egg yolk does the work: its molecules… Food Science4 min read11 Oct Why the bottom of a dropped Slinky hangs in mid-air: a wave has to bring the news Hold a Slinky by its top, let it stretch, and let go. The top rushes down while the bottom coil hovers, apparently ignoring gravity, until the collapsing coils… Physics5 min read11 Oct How thousands of fireflies flash in time with no leader: pulse-coupled oscillators On riverbank trees in Southeast Asia, thousands of male fireflies flash together, with no leader and no shared clock. Each insect is just a small timer that… Biology4 min read11 Oct How a stick and a well measured the whole Earth: Eratosthenes Around 240 BC, the librarian Eratosthenes measured the size of the Earth using a well, a stick and a shadow. At noon on the summer solstice the sun shone… History4 min read11 Oct Why switching doors wins twice as often: the Monty Hall problem Three doors, one car. You pick one, the host opens a goat door, and offers a swap. Most people say it's 50/50. It isn't: switching wins twice as often as… Maths4 min read10 Oct How astronomers measure a star's distance by looking from both sides of the Earth's orbit: parallax Hold a thumb at arm's length and blink one eye, then the other: the thumb jumps against the background. Astronomers do the same with the whole orbit of the… Earth & Space4 min read10 Oct