Recently, I attended a staff seminar where the theme of resonance was used. According to Wikipedia, resonance is a term used in physics whereby one system tends to oscillate a maximum amplitude at certain frequency.
Resonance is a powerful force multiplier. It is both a natural and artificial phenomenon whereby something moves in synchrony with another, for both good and bad. Witness how the powerful high pitched voices of soprano singers can cause wine glasses to shatter.
Marching soldiers crossing a wooden bridge at a certain rhythm can cause it to break. Even helicopters like the almighty Chinook can fall prey to Resonance! Watch this video below: