There is a category of human behaviour that is universal, immediately recognisable across every culture, entirely involuntary, and without a settled explanation.
Emotional crying belongs in it, alongside blushing and…
The wheel is frequently described as the great invention. The wheel-and-axle pair is the invention; a disc that rolls is obvious, and attaching it usefully is not. Here are twelve…
The useful way to think about paint is as a delivery system. The colour cannot stick to anything by itself, so the entire technology is about getting it onto a…
There is a general expectation that pain corresponds to damage. A large injury should hurt more than a small one, and a deep wound more than a superficial one.
A…
Navigation problems divide into two parts, and confusing them is the reason this subject seems simpler than it is.
The first is knowing which way you are facing. A compass…
Most visible human variation is complicated. Height, skin tone, hair texture and facial structure each involve many genes contributing small effects, which is why they vary continuously rather than falling…