The interactive scale of the Universe

This article from Bad Astronomy (actually a very good website, its name came from Phil's desire debunk the bad astronomy found in hoax sites) links to a very useful interactive demonstration of the relative size of things in the Universe from far smaller than an atom, to the size of the known universe.

It will be very usefully in getting a handle on the relative size of things, plus get an understanding of modern physics and astronomy, with the size of biological things somewhere in the "middle" of the size scale.