This is a routine high school physics experiment.<p>I did a speed of light measurement in high school physics. We had a prism mirror on a 30,000 RPM motor, a slit lamp (not a laser) and some mirrors.  The narrow bar of light from the slit lamp was aimed at the prism, which reflected the light to a distant mirror, then back to the prism, then onto a target.  The idea is that as the motor RPM increases, the line of light projected onto the target will move slightly, and you can calculate the speed of light from this.<p>We didn&#x27;t have a dark enough or long enough room, and aligning all the mirrors was a huge pain.  We could see the line of light move slightly as the motor speed increased, but our baseline was too short to get enough movement to measure accurately.