Stories from Physics for 11-14 14-16
In 2011, the Korea Times reported that an exercise class caused large vertical vibrations in a 39-storey shopping mall in Seoul. A Tae Bo exercise class (a mix of taekwondo and boxing) taking place on the 12 th floor caused oscillations that could be felt on a number of other storeys. Inspectors recreated the conditions of the phenomenon by asking 23 people to carry out Tae Bo exercises whilst they used laser Doppler vibrometers to monitor the transfer of oscillations. They noted vibrations on the 38 th floor were ten times the expected amplitude and concluded that the frequency of the Tae Bo exercises matched the resonant frequency of the building.