Category Science

The holes, called docker holes, let steam escape while the cracker bakes. Without them the dough blisters into a lumpy pillow, as two snack and pizza patents explain.

The mirror-image word on the front of an ambulance turns the right way round in a rear-view mirror. In the US it is a written rule: federal specification KKK-A-1822 sets the letters at no less than 4 inches, in blue.

There is no universal code for scrub colours. The green in operating rooms goes back to a 1914 article by surgeon Harry Sherman, whose green sheets faded in sterilization, so he dressed his team in black.

For decades textbooks said microbes outnumber your own cells ten to one. The real figure is closer to a tie, and the story of the old number is its own lesson.

You have probably heard that medieval windows are thicker at the bottom because glass slowly drips over centuries. It is a tidy story, and it is false.