Jill in Denver asks: What the heck is "Brownian Motion"?
Thank you for the question, Jill. Brownian Motion was discovered by observing the jumpy movement of a pollen grain in liquid. It is named for Scottish botanist Robert Brown (1773 - 1858), who identified it in 1827.
Its importance lies in the fact that this movement, caused by atoms and molecules in the water hitting the grain, was used by Albert Einstein as proof of the existence of atoms -- before it was possible to see such small items through a microscope.
Brownian Motion has gone on to be used in mathematical contexts involving the random generation of numbers.
The illustration is by famed naturalist Charles Harper.