Killing Time

I was reading up on the concept of time the other day and was introduced to the concept of entrainment, a concept I found most interesting.

The eminent dutch philosopher, mathematician and scientist Christiaan Huygens (1629-1695) was one of the great fathers of horology. He invented the most accurate clock of his time, the pendulum clock, in 1656. Huygens noticed that when he had two pendulum clocks in proximity to each other that eventually they would synchronize their swings and tick at the same time. He called this phenomenon odd sympathy.

These coupled oscillations are what is now known as entrainment. Independent bodies that end up finding a synchronous frequency. Outstanding. The technical reason is this happens because energy is transferred between the two systems when they are out of phase and they produce negative feedback. They eventually assume a more stable phase relationship, and the amount of energy gradually reduces to zero. Ask and I will give you the hippie version later.

Other harmonic relationships are also possible besides total synchrony, they can be asymmetric, where the system with the greater frequency slows down, and the other speeds up, and they can also give rise to what is known as a "death state"where the clock finally stops. By the way, in Huygens's initial example the energy was found to have been transferred by the wooden mantle that the clocks were both sitting on.

Huygens discoveries regarding resonance are now used in many common modern applications, from hearing aids to pacemakers.