Description: This is a trick to make a ringing sound eminate from a wine glass.
To make a wine glass produce a faint humming sound, get a wine glass made from real glass.
Wet your finger with water and put your finger on the top edge of the glass.
Start moving your finger in a circle around the glass with a little pressure.
Result: After circling the glass at least once you should begin to hear a faint singing coming from the glass.