The angle at the apex of the wake of a boat is fixed at about 40 degrees, irrespective of a boat’s speed. This pattern is called a Kelvin wake. Photograph: Getty Images

A stone dropped in a pond generates waves in a beautiful changing pattern, a rippling ring radiating outward from a centre that gradually retur(...)

The Pitch Drop experiment

Later this year a big black blob of sticky pitch will plummet from a funnel and plop into a beaker. In one of the longest-running physics exper(...)