In 1665, whilst working on the design of the pendulum clock, scientist Christiaan Huygens hung a number of prototypes on the walls of his workshop. He wanted to know just how efficient they were and whether they would still be swinging the following day. So he swung all the pendulums then went home to bed for the night.
The next morning he returned to his workshop to find that, although he had swung them all at different intervals, the pendulums were swinging in time with each other, albeit in opposite directions.
This mysterious phenomenon, known as coupled oscillation can be explained in that the clocks all have a mutual influence on each another. A gravitation towards spontaneous order.
Kind of like this video here:
Wobbly Bridges And Synchronisation
In 2000 the new Millennium bridge in London had to be closed after it started to laterally swing out of control on opening day to the point where pedestrians couldn’t walk. The structural engineers and project team had rigorously tested every aspect of the bridge, including the affect of crowds on the bridge. However, What they had failed to consider was the power of group behaviour. They tested the affect of crowds on the bridge behaving randomly. What they hadn’t expected, was that groups of people would in effect behave in sync. Have a look at the power of group sleeping aids dynamics in the video below.
In the footage, you can see pedestrians start to walk in synchronisation in order to balance their movements. They were not intentionally trying to walk in unison, they were only trying to accommodate the bridge’s movement and simply ended up walking in time. As more and more people did this, they influenced the bridge to swing more and this exchange of rhythmic influences increased until people could barely walk.
According to reports after the incident, the critical number of people to influence the wobbling of the bridge was 160. There were 2,000 people on the Millennium Bridge at any one time on that day. So everyone walked at the same time, to create a synchronised rather than random force. This frequency matched the natural frequency of the bridge. The motion of the crowd synchronised with the motion of the bridge.
The bridge was later mended (at a cost of $8.9 million dollars) with 91 dampers added to stop both the vertical and lateral oscillation.
Music is perhaps the best example of synchronisation. When two people create a syncopated rhythm together they are demonstrating the very essence of teamwork in action. By understanding what drives us to connect the way we do through music we can understand and apply one of our most natural behaviours to some of our most difficult challenges – simply getting along.