A Sense Of Scale

There have been other attempts in the past, so this is not strictly a new idea. However I found the interactive web page at http://htwins.net/scale2/ extremely well constructed.

It is a graphical display of the largest and smallest structures from galaxy superclusters down to quarks and the Planck length. By moving a scroll bar left or right, you can get a very clear sense of scale of the different things. And in so doing you learn the relative size of different objects, from planets to stars, or from stars to galaxies; or vice-versa, from cells to molecules and atoms.

I highly recommend it!