The same wind speed can mean twice the pressure, depending on its averaging time
Wind pressure follows the square of the speed, so whether a figure is a 3-second gust or a 10-minute mean can more than...
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Thunder covers a kilometre in under three seconds in Singapore air
Dividing the seconds between a lightning flash and its thunder by three gives kilometres, but in Singapore's air sound c...
Rare blood-group variants allow most of the child blood types a chart forbids
The textbook ABO rule forbids at least one child blood type for every pairing of parent types except A with B. Rare inhe...
QT correction formulas agree at 60 beats a minute and drift apart either side
Bazett, Fridericia and Framingham correct the QT interval to a heart rate of 60 beats a minute, where all three give the...
Why stopping distance charts disagree at the same speed
At 90 km/h, Singapore's driving handbook says 95 metres, Britain's table gives 73 at a slightly higher speed, and US roa...
The 24 solar terms in 2026, and why the date moves every year
A solar term is a moment, not a day: 寒露 2026 is 8 October at 14:29. Here are all 24 with their times, matching the Hon...
How many ancestors did you have a thousand years ago?
Doubling every generation gives you about a trillion ancestors a thousand years back, more people than have ever lived....
Two published rules for the new moon disagree about one month in three
MABIMS and Muhammadiyah's wujudul hilal are both published and computable a year ahead. Worked through fourteen lunation...
Singapore's humidity swings thirty points a day without the water changing
Relative humidity is a ratio whose denominator moves with temperature, so 70% at 31°C holds two and a half times the wat...
The pressure on your tyre's sidewall is a ceiling, not an instruction
The sidewall figure belongs to the tyre; the door-pillar placard belongs to the car, and it is the one to follow. But th...
The octane numbers on American and Asian pumps are not the same scale
American 87 is roughly 91 RON, because the United States posts the average of two laboratory tests while most of the wor...
22.4 litres is only correct if you say at what pressure
A mole of ideal gas occupies 22.414 litres at one atmosphere and 22.711 litres at one bar, and NIST publishes both as se...
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