Here's an easy way to measure the speed of light in your classroom without wrecking your budget.
By replacing large, expensive rotating mirrors with electronic and fiber optic technology, this money- and space-saving apparatus lets you conduct light speed measurements right from your desk.
The protected, slim circuit board generates pulse signals that travel the length of the included 20-meter fiber optics cable to a special receiver. Using a dual-track oscilloscope (not included) you can directly monitor the pulse signals on one channel, while the second channel records the results from the receiver and displays the two signals with their phase difference. You simply calculate the speed of light from the length of the cable and the phase difference. Includes a history of the study of the speed of light. 120v 60hz.