Student Resources for General Chemistry

Here, we show you various standing waves. By keeping the ends of a Wave Demonstrator fixed, we see that certain frequencies allow constructive interference with themselves. In other words, when the wave bounces back from the end of the demonstrator, it has the same phase as the incoming wave, so they constructively interfere. In this way, the wave 'stands' and maintains it's existence longer. If there were no friction within the device, the same pattern would continue. The inset gives the frequency (which is directly related to the energy) of the vibration. It is possible to imagine these standing waves as a state of 'existence' for the wave (because it does not destroy itself by destructive interference). Let's approximate the energy of the first video to be 0.80. Do you see a pattern in the numbers following?