On April 11, 2024, Dr. Nosonovsky delivered a lecture at the Braginsky Center for the Interface between Science and the Humanities of Weizmann Institute of Science in Rehovot, Israel. The topic of the lecture was “Friction and Time Measurement: How the Invention of the Pendulum Made Clocks Much More Accurate.”

The lecture caused some interest among Weizmann Institute’s scientists. A Nobel Prize winner, Prof. Ada Yonath (2009 Nobel Prize in Chemistry, 2006 Wolf Prize in Chemistry), attended the lecture, which is a great honor for the lecturer.

Friction and Time Measurement: How the Invention of the Pendulum Made Clocks Much More Accurate
Prof. Michael Nosonovsky (University of Wisconsin-Milwaukee)

Mechanical clocks appeared in Europe at the end of the thirteenth century and became widespread during the fourteenth century. Clocks utilized a periodic process – the oscillation of a verge – for accurate time measurement, which is consistent with the Aristotelian concept of time defined by motion. The concept was at the center of debates among scholastics and theologians, which culminated in the Church’s Condemnation of Aristotelian teaching in 1277. The debate also led to the discovery of Impetus (inertial motion) by Buridan and Oresme. Interestingly, sand clocks became a popular device at about the same time reflecting the interest in accurate time measurement.

The pendulum clock invented by Huygens in the 1650s utilized linear oscillations, which, unlike the earlier verge mechanism, had their natural frequency. The verge mechanism provided a relatively low accuracy of time measurement. The introduction of the pendulum improved the accuracy by about 30 times. The improvement is attributed to the isochronicity of small linear vibrations of a mathematical pendulum. Using scaling arguments, we show that the introduction of the pendulum resulted in accuracy improvement by approximately π/μ ≈ 31 times, where μ ≈ 0.1 is the coefficient of friction.