What the fourth decimal on your stopwatch means
00:04.2137 — that last digit is real, not padding. It is also not an accuracy claim. The difference between resolution, precision and accuracy, told through our own app's code.
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Why your phone's clock is right and your wall clock isn't
In 2018, every mains-powered clock in Europe lost six minutes because the grid drifted by four thousandths of a hertz. No phone noticed. The difference is correction — and the correction is also the one thing that can touch a running stopwatch.
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Does daylight saving time actually do anything?
The energy savings round to zero, the heart-attack spike is real but almost always misquoted, and the sleep-medicine consensus recommends the opposite of what the US House just voted for. What the studies actually measured.
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How do you calibrate the world's most accurate clock?
In June 1955 the steadiest timekeeper on Earth began ticking — and nothing steady enough to check it against existed. So it was tied to Greenwich, then to the Moon, and finally defined.
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What is a time zone?
In Kashgar, the sun can reach its highest point at ten past three in the afternoon. That is not astronomy — it is politics, and once you see it, the whole map of time makes sense.
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The second that keeps getting added, and may soon be subtracted
Twenty-seven times, a minute has lasted sixty-one seconds. It broke Reddit, grounded check-in desks, and is now being retired — just as the Earth started spinning fast enough to need the opposite.
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Why two stopwatches started together drift apart
Start two identical timers at the same instant and come back tomorrow. They disagree — and the reasons are a tuning fork, a parabola, and the temperature of wherever you left them.
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How long is a moment?
It used to have an answer. So did the atom, the jiffy and the shake — units invented centuries before anything could measure them, by people who were counting rather than timing.
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The railways invented the time you live by
Until 1840 every English town kept its own noon, and nobody minded. Then something started moving faster than the sun — and the clocks had to be argued into agreement.
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Why a minute has sixty seconds
Sixty is a strange number to hang a civilisation's timekeeping on. The answer runs from Sumer to a Kassel workshop to a French decree that made noon five o'clock — and lasted seventeen months.
