Science
Why we have leap years, and why some are skipped
A year is not a whole number of days. Every calendar rule since has been an attempt to manage the…
Facts
A fact is only interesting once you know why it is true. Each piece here takes something you have half-heard, why the sky is blue, why the Moon shows one face, why onions sting, and explains the mechanism underneath it, in plain language and without hand-waving.
Science
Why the wind blows, and why it does not blow straight
Air moves from high pressure to low pressure. It then gets deflected by the rotation of the planet, which is why weather maps look the way they do.
Read more: Why the wind blows, and why it does not blow straight
Science
Why the tide comes in twice a day
The Moon pulls the ocean towards it, which explains one bulge. The second one, on the opposite side of the…
Science
Why ice floats, and why almost nothing else does
Nearly every substance is denser as a solid than as a liquid. Water is not, and a great deal depends…
Science
Why the sea is salty, and why rivers are not
Rivers carry salt to the sea continuously. The interesting question is not why the sea is salty but why the…
Science
Why the sky is blue, and why it is not violet
Rayleigh scattering separates sunlight on the way down. The same physics explains red sunsets, white clouds, and why Mars has…
Animals
An octopus has three hearts, and that is why it would rather walk than swim
An octopus has three hearts because its blue blood carries oxygen poorly. The interesting consequence is that swimming stops one…
Space
Why the Moon always shows us the same face
The Moon shows one face because it rotates, not because it does not. Tidal locking explains why, and libration lets…
Science
Why onions make you cry
An onion builds its irritant only when you cut it. Knowing the reaction tells you which of the usual kitchen…