There is a security feature in almost everyone's pocket that has been doing its job for over three hundred years, and almost nobody knows what it is for.
Look at…
The useful way to read a lock is as a question about what the key is proving. Every mechanism below tests something slightly different, and the differences are the history.…
Almost none of these are about a single person doing a small thing. They are about what a small thing becomes when several million people do it in a year.…
Almost every unit of time you use is a measurement of something physical.
The day is the Earth turning once. The month is roughly the Moon going through its phases.…
Blood Types Were Discovered Over a Century Ago and Nobody Has Established What They Are Actually For
Most people know their blood type, treat it as a fixed personal fact like eye colour, and have never wondered what it is.
It is a molecule. Specifically, blood type…
A single phone in a shared space produced an entire social system, and everyone who lived through it remembers the same rules. Here are twelve.
1. It Lived in the…