Announcements

We are pleased to announce that the Best Presentation Award of the XLVII Congress of Polish Physicists 2021, sponsored by Entropy (ISSN: 1099-4300), has been granted to Dr. David Ziemkiewicz from Bydgoszcz University of Science and Technology. Congratulations!

Title: “Chaotic Dynamics of the Clock Mechanism”

For centuries, the mechanical pendulum clock has been one of the primary means of measuring time. Its central part is a damped pendulum, kept in motion by the exciting force, the nature of which depends on the type of clock mechanism. The mechanism supplies energy to the pendulum and is simultaneously regulated by it; it is a special case of a self-excited oscillator, and the current feedback makes the dynamics of the system non-linear and often chaotic, with a fractal attractor. In the history of clock development, most attempts to improve the precision of timing have been based on reducing the influence of non-linear effects by minimizing the interaction between the pendulum and the mechanism—so that it is a good approximation of a mathematical free pendulum. A completely different approach was proposed in 1722 by John Harrison. In its construction, the pendulum is in constant contact with the mechanism and vibrates with a very large amplitude. Thanks to modern numerical methods, it is possible to perform a detailed analysis of this type of system (D. Ziemkiewicz, Phys. Rev. E 2021, 103, 062208). It can be shown that under appropriate conditions (correctly identified by Harrison), one can obtain an error of indications at the level of a few seconds per year, which is an unattainable value for other types of mechanical clocks.