I received this through email and thought it was a nice demonstration of the <a href="http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/">Powers of 10</a>. If you've been to the Hayden Planetarium in New York City, this will be familiar to you, but it doesn't go quite as far as that one does. This Java applet lets you navigate from 10<span style="vertical-align: super; font-size: smaller">23</span>, <iq>10 million light years from the Milky Way Galaxy</iq> to 10<span style="vertical-align: super; font-size: smaller">-15</span>, <iq>face to face with a proton</iq>. Be patient, sometimes it takes a few seconds to load the next frame once you click an arrow.