Scientists were successful in solving a nearly 360-year-old mystery of why pendulum clocks hanging from the same wall synchronize over time. Scientists came to conclusion after analyzing two pendulum clocks that were hanging from the same beam.

Dutch physicist Christiaan Huygens almost 350 years ago invented a pendulum clock. He noted that no matter how the pendulums on two clocks hanging on from the same wall began, within about half hour they ended up swinging in exactly the opposite direction from each other. But the cause of this effect remained mystery for centuries.

But scientists at the University of Lisbon in Portugal decided to analyze how two pendulums might interact through an immobile wall. They found that the clocks could influence each other through small forces exerted on the supporting beam.

Henrique Oliveira and study co-author Luis Melo calculated that as pendulums move back and forth, sound pulses could travel through the wall from clock to clock. These sound pulses can interfere with the swings of the pendulums, eventually making them to synchronize.

These waves that are sound matter them to synchronization and in the end can affect the style in which the pendulum swings. The dunes driving one pendulum with time together with the other vacation and come back to the metal club.

Furthermore, researchers tested their idea with experiments involving two pendulum clocks attached to an aluminum rail fixed to a wall. Results showed that changes in the speed of the pendulum swings matched with cycles of the sound pulses.