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Some things everybody knows are true. Others everybody knows, and they are not. This series takes one widely repeated belief at a time and looks at what is actually known about it.
Often the answer is neither a clean yes nor a clean no: the belief turns out to be half right, or right for the wrong reason. Each article explains how we know, and the newer ones list the sources they used.
Fact-based How It Started
The tea bag is said to have been born by mistake, when customers dunked silk sample pouches around 1908, but two women in Milwaukee had already filed a patent for one in 1901.
Fact-based Cosmic Questions
The Moon does spin, but exactly once for every trip round the Earth, so one side always faces us, and the side we never see is not dark at all.
Fact-based Cosmic Questions
The yellow in an autumn leaf was hiding there all summer, the red is made fresh in its last weeks, and the frost that usually gets the credit actually spoils the show.
Fact-based Weird Facts
Everest wins only if you measure from sea level: a Hawaiian volcano is taller from foot to top, and a peak in Ecuador stands farther from the centre of the Earth.
Fact-based Kitchen Science
A bar forgotten at the back of a cupboard can come out dusty and grey, and the reason is that the same fat inside it can set in at least six different ways.
Fact-based Cosmic Questions
The stars are not flickering at all: their light is being nudged about by the air above your head, and a planet looks calm for a surprisingly simple reason.
Fact-based Weird Facts
The internet loves sleeping otters holding paws, but in the wild it is a rare sight, and the anchor most otters trust for a nap is a strand of kelp.
Fact-based Word Journeys
A popular story says kangaroo means I don't understand, but the word was a real name for a big grey kangaroo, written down beside a river in 1770.
Fact-based Kitchen Science
Heat a pan of sugar and it seems to melt into a golden pool, but the molecules are already breaking down, which is why good caramel depends on time as much as on heat.
Fact-based Odd Places
From space, a bull's-eye about 40 kilometres wide stares up out of the desert in Mauritania, and the way it formed is slower and stranger than any falling rock from the sky.
Fact-based How It Started
The grey core of a pencil is graphite, a soft form of carbon, and the lead in its name comes from a mix-up on an English hillside more than 450 years ago.
Fact-based Weird Facts
A chameleon is not a living copy machine for whatever it sits on: its most dazzling colour changes are messages to other chameleons, made with tiny crystals in its skin.
Fact-based Weird Facts
The small cumulus drifting over your garden is carrying roughly five hundred tonnes of water, and it stays up there for a reason that has nothing to do with being light.
Fact-based Kitchen Science
A loaf sealed so tightly that not a drop of water can escape will still go stale, because staling is the starch quietly rearranging itself rather than the bread drying out.
Fact-based Weird Facts
A hippo climbing out of a river shines orange-red in the sun, and that glossy coat is a sunscreen it makes in its own skin, one that keeps germs away as well.
Fact-based Weird Facts
The famously forgetful goldfish can remember things for months, learn to press a lever for food, work out what time dinner is served and tell its owner apart from other people.
Fact-based Weird Facts
It is one of the most repeated facts in the world, and it is wrong: from the Moon the wall is invisible, and even from orbit it is so hard to spot that astronauts argue about it.
Fact-based Cosmic Questions
A rising full moon can look enormous, yet a camera shows it is no wider than when it rides high in the sky, which means the giant moon is being built inside your head.
Fact-based Weird Facts
A baby flamingo hatches fluffy and pale grey, and it only turns that famous pink because of what it eats, a colour its parents can lose again while feeding it.
Fact-based Weird Facts
The old saying is wrong: tall, pointy, isolated things are struck again and again, and New York's Empire State Building takes an average of 23 hits a year.
Fact-based Weird Facts
Slow on the ground, sloths float thanks to gas from digesting leaves, keep their noses up like a snorkel and swim about three times faster than they walk.
Fact-based Weird Facts
Fungi really do live on tree roots and help trees grow. Whether they link whole forests into a sharing network is far less certain than the popular story says.
Fact-based Weird Facts
The bag says raw, the shop says raw, and it is not raw — because the shell it came out of holds an oil that irritates skin much like poison ivy does.
Fact-based Weird Facts
Every clownfish starts adult life as a male, and when the female who rules an anemone disappears, her partner turns into a female and takes her place, so in a real reef Marlin would have become Nemo's mum.
Fact-based Weird Facts
Stegosaurus lived around 150 million years ago, T. rex about 68 to 66 million years ago. We are closer in time to T. rex than it was to Stegosaurus.
Fact-based Weird Facts
Polar bear fur has no white pigment at all: the guard hairs are transparent and hollow, the white comes from scattered light, and the skin underneath is black.
Fact-based Weird Facts
Honey is too dry, too acidic and too sugary for most microbes to survive in, which is why a jar at the back of the cupboard is almost always still good.
Fact-based Weird Facts
The Great Pyramid was already about 2,500 years old in her time. The first Moon landing came about 2,000 years after her.