Humble Pi: When Math Goes Wrong in the Real World

by Matt Parker

Resonance can affect buildings as well. In July 2011, a thirty-nine-story shopping center in South Korea had to be evacuated because resonance was vibrating the building. People at the top of the building felt it start to shake, as if someone had banged the bass and turned up the treble. Which was exactly the problem. After the official investigators had ruled out an earthquake, they found the culprit was an exercise class on the twelfth floor. On July 5, 2011, they had decided to work out to Snap!’s “The Power,” and everyone jumped around harder than they usually did. Could the rhythm of “The Power” match a resonant frequency of the building? During the investigation, about twenty people were crammed back into that room to re-create the exercise class and, sure enough, they did have the power. When the exercise class on the twelfth floor had “The Power,” the thirty-eighth floor started shaking around ten times more than it normally did.