A group of researchers may have finally found the answer to the mysteries surrounding the perfectly synchronized manner of swinging by two pendulum clocks.
The flawless dance of two pendulum clocks was first observed by Christiaan Huygens in 1665. He was then sick and stuck to his bed that time when he noticed that the two pendulum clocks hanging on their wall swayed in sync to one another, regardless of when it was started or stopped, or no matter what position they may be placed.
In this new study, the researchers from the University of Lisbon found that the rationale for Huygen's long-time discovery may be explained by sound waves.
Researchers Henrique M. Oliveira and Luís V. Melo performed the study by devising an experiment that used a standard optical rail rigorously attached to the wall where two pendulum clocks with a distance of 230 millimeters were also fixed.
The said distance is the smallest possible measurement that can ensure that the two pendulums would not bump into each other. The anchor-pendulum clocks used were mass-driven and, according to the scientists, one mass travel can provide energy that can last for up to five days. The clocks won't die down instantly as it would take approximately one day for it to relax under its final frequency after winding. The period is adjusted by lengthening the actual pendulum through manipulation of the screws at the bottom of the clocks.
The findings of the study, published in the journal Nature, show that, based on the calculations made by the researchers during the back and forth swinging of the clocks, sound pulses could be transmitted through the wall from one clock to the other. These sound waves can influence the manner in which the pendulum swings and eventually subject them to synchronization. The waves travel and return to the aluminum bar, pushing one pendulum in time with the other.
"We could ... verify that the energy transfer is through a sound pulse," co-author Melo, from Lisbon University's physics department, said. More than uncovering the mystery behind an old scientific puzzle, their study was also able to enhance understanding about how other types of oscillators work, he added.
Huygens created the first pendulum clock in 1656, which was considered the most accurate device that could tell the time. The initial error margin of his invention was one minute in a day but it was later decreased to under 10 seconds.