The test is simple: pigment colour looks the same from every angle, and structural colour changes as you move. Once you know that, a great deal of the natural world…
Ask most people whether counting is natural and they will say obviously yes. Every culture counts. Children learn numbers early. It feels less like a skill than a faculty.
The…
Pitch depends on how fast something vibrates, and everything below is a different method of controlling that rate and then getting the vibration into the air loudly enough to hear.…
Ice cubes float. This is so ordinary that it takes a moment to see anything strange in it.
Consider what floating means. An object floats when it is less dense…
Soap is one of the oldest manufactured substances and one of the most consequential, and almost nobody can explain what it does.
The common assumption is that soap is a…
The fossil record is overwhelmingly a record of hard parts.
Bones, teeth and shells survive because they are mineral to begin with. Everything else — muscle, skin, fur, feathers, gut…