You know that light travels at a very high speed. But did you also know that light travels at different speeds in different environments? In this interactive activity from from the NOVA Web site, you'll learn that transparent objects, such as glass, cause light to slow down, and that this change in speed actually causes light to bend, a phenomenon known as refraction.
Note: This feature originally appeared, in slightly different form, on NOVA's Einstein Revealed Web site as Joe's Room, which has been subsumed into the Einstein's Big Idea Web site.
This resource can be found on the NOVA: Einstein's Big Idea website.