Resonance When an opera singer vibrates a glass with their voice, they have matched the resonant frequency of the glass. As the singer increases the volume of their sound, the resonance becomes too great for the forces that hold the glass together and it shatters. Modern medicine now uses sound waves to break up kidney stones and gallstones. Every organ, bone, and cell in the body has its own resonant frequency. Together they make up a composite frequency like the instruments of an orchestra. When one organ in the body is out of tune it will affect the whole body. Through sound healing it may be possible to bring the diseased organ into harmony with the rest of the body, hence avoiding the need for drugs or surgery. The principle of entrainment states that powerful vibrations from one source will cause less powerful vibrations of another source to lock into the vibration of the first. Nature always seeks the most efficient state; it takes less energy to pulse in co-operation that in opposition. Scientific Research into Sound In the 18th century, Ernest Chladni, a German physicist, found that when a violin bow was drawn vertically across the rim of a metal plate the sound waves produced created patterns