Facts

Things that are true and hard to believe.

Every one is real, sourced, and says so where the evidence is contested. Tap any card for the full explanation.

153 facts

Language

A language was born in front of researchers in the 1980s

Deaf Nicaraguan children were brought together, given no sign language, and invented one.

Why this is true
Physics

Gallium melts in your hand

A metal with a melting point below body temperature.

Why this is true
Language

Basque is related to no other language on Earth

Surrounded by Romance languages, descended from none of them.

Why this is true
Physics

Superfluid helium climbs out of its own container

Cooled far enough, it flows with no viscosity and creeps up the walls.

Why this is true
Things that are false

Shakespeare did not coin as many words as you were told

He is the first recorded use of many words. That is a different claim.

Why this is true
Physics

Light has been slowed to the speed of a bicycle

And then stopped entirely, and then released again.

Why this is true
Things that are false

QWERTY was not designed to slow typists down

The jamming story is repeated everywhere and rests on very little.

Why this is true
Physics

Bananas are measurably radioactive

So are you, and so is anyone you hug.

Why this is true
Language

One Amazonian language appears to have no exact numbers

Roughly one, roughly two, many. And speakers struggle with exact matching tasks above three.

Why this is true
Physics

A second is defined by a caesium atom, not the Earth

Exactly 9,192,631,770 oscillations. The planet turned out to be an unreliable clock.

Why this is true
Language

OK began as a joke about bad spelling

From a fad for comic abbreviations in 1830s Boston newspapers.

Why this is true
Physics

Most of Earth’s gold probably came from colliding neutron stars

Ordinary stars cannot make it. Something more violent had to.

Why this is true
Language

Writing was probably invented for accounting

The oldest substantial texts are receipts, not poetry.

Why this is true
Physics

Nuclear testing left a timestamp in every living thing

Atmospheric bomb tests doubled carbon-14, and biology recorded the spike.

Why this is true
Numbers

Zero took centuries to be accepted in Europe

Some Italian cities banned it as an invitation to fraud.

Why this is true
Numbers

Twenty-three people give you a better than even chance of a shared birthday

It feels like it should take hundreds. It takes a small classroom.

Why this is true
The mind

Studying for an exam in the room you will sit it in helps

Divers who learned word lists underwater recalled them better underwater.

Why this is true
Numbers

Fold a piece of paper 42 times and it reaches the Moon

In principle. In practice you will stop at about seven.

Why this is true
Things that are false

We only use ten per cent of our brains is completely false

Scans show essentially all of it active over the course of a day. Damage anywhere causes deficits.

Why this is true
Numbers

Switching doors doubles your odds, and almost nobody believes it

Professional mathematicians wrote in to say it was wrong. It was not.

Why this is true
Numbers

Real-world numbers start with 1 far more often than chance allows

About 30 per cent of the time. Tax authorities use this to catch fraud.

Why this is true
Numbers

Some infinities are bigger than others

There are more numbers between 0 and 1 than there are whole numbers, and it can be proved in a paragraph.

Why this is true
Numbers

NASA uses only fifteen decimal places of pi

Enough to calculate a circle the size of the solar system to within a centimetre.

Why this is true
Numbers

Rice on a chessboard bankrupts a kingdom

One grain on the first square, doubling each time. By square 64 you owe more rice than exists.

Why this is true