Odd Sympathy

The term “odd sympathy” was coined by the 17th-century Dutch mathematician and physicist Christiaan Huygens to describe the strange phenomenon he observed while laying sick in bed and looking up at two of his newly invented pendulum clocks hanging on the wall beside him. Inexplicably, the two pendulums always swung in opposite directions. Even when he would release them in different positions, they eventually fell back in synch (or antisynch, to be precise). Huygens had discovered the principle of coupled oscillation, but it took a recent study by physicists at Georgia Tech to prove that it was the miniscule force of the pendulums operating on a beam in the wall that caused them to link up.