Move a Match with Your Mind?

1. Fill each glass with equal amounts of water (about half-full seems to work well).
2. Hold the stem of the glass with one hand and dip the index finger of your other hand into the water.
3. Rest your finger on the rim of the glass, press down slightly, and rub it all the way around the rim without stopping. Keep going in a circular motion along the lip of the glass while maintaining the pressure, and, in almost no time, you’ll have displayed a newfound musical talent.
4. Once you've mastered the art of making the wine glass sing, do the same thing with the other wine glass. You want the tone from each glass to be the same. This means that you will need to adjust the amount of water in each glass so that the tone is exactly the same.
5. Here's the fun part. Rest a stick match on the rim of one of the glasses. Position the second wine glass close to the first one, but make sure they're not touching. Dip your finger in the water and make the glass without the match sing, but don't take your eyes off the match. What? The match moves! How does that work?

How does it work?

There are really two parts to this activity... the singing of the wine glass and the movement of the match. Let's discuss the singing wine glass first.  As you rub your finger on the rim, your finger first sticks to the glass and then slides. This stick and slide action occurs in very short lengths and produces a vibration inside the glass which in turn produces a sound. As soon as the first few vibrations are produced, the glass resonates. That means you’re causing the crystals in the glass to vibrate together and create one clear tone. You can change the pitch (highness or lowness of the sound) by adding to or subtracting from the amount of water in the glass. The volume (loud or quiet) can be changed only a little bit by increasing or decreasing the pressure from your finger. 

The movement of the match is caused by a sympathetic vibration. Because you added equal amounts of water, the second glass vibrates at exactly the same frequency as the first. The sound waves produced by the first glass travel in every direction. When those sound waves reach the second glass, the glass begins to vibrate as well and the match moves. Telekinesis? Nope... just some really clever science.