ABSTRACT
The first all-mechanical clocks were invented in Europe toward the end of the 13th century. They were based on spring-loaded balance wheels that transferred the motion of the oscillating wheel to a stick with teeth that eventually transferred the motion to the hands of the clock. Science today operates with an ever-growing accuracy, and with shorter and shorter units of time. The first national atomic clock standard was established at the National Physics Laboratory in England. The basic principle of atomic clocks is all about determining the precise oscillation of a kind of pendulum. Entropy is a classical concept of thermodynamics that was developed during the latter half of the 19th century when scientists and engineers were getting a deeper understanding of what was happening in steam engines.
