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Why a dam is fat at the bottom: water's push grows with depth squared, its tipping with depth cubed A dam is fat at the bottom and slim at the top because water pressure grows with depth, so the push grows with depth squared and the tipping effect with depth… Engineering5 min read26 Oct Why bridges are made of triangles: a square folds, a triangle cannot A square made of four pinned rods folds flat at the slightest push, but a triangle of three rods cannot change shape at all. That one fact is why bridges… Engineering3 min read22 Oct Why steel beams are shaped like an I: the same steel, 25 times stiffer Put a beam across a gap and it sags: the top edge is squeezed, the bottom stretched, and the steel in the middle does almost nothing. That is why girders are… Engineering4 min read15 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 a squeezed ruler bows sideways: Euler's buckling and the hollow tube Squeeze a ruler between your palms and it doesn't crush: it bows sideways and gives way. That's buckling, and it decides how slender a column can be. Euler… Engineering4 min read9 Oct Why every bridge is made of triangles: a square frame folds, a triangle can't Push on the corner of a square frame and it folds flat. Push on a triangle made of the same sticks and nothing moves. The reason is simple: three side lengths… Engineering4 min read6 Oct How a Bloom filter says "definitely not" using just a few bits How can a computer check whether a word is on a huge list using only a few bits per entry? A Bloom filter flips a handful of switches for every word you add… Computing3 min read3 Oct Hang a chain, flip it upside down, and you have the perfect arch In 1675 Robert Hooke hid a building secret in an anagram. Decoded after his death, it said: as hangs a flexible cable, so, inverted, stand the touching pieces… Engineering5 min read27 Sep