Galileo's Pendulum

From the notes of Professor Fred L. Wilson, The Rochester Institute of Technology:

The first of his [Galileo's] startling discoveries took place in 1581, when he was a teenager   studying medicine at the University of Pisa. Attending services at the Cathedral of Pisa,    he found himself watching a swinging chandelier, which air currents shifted now in wide   arcs, now in small ones. To Galileo's quantitative mind, it seemed that the time of swing   was the same, regardless of the amplitude. He tested this by his pulsebeat. Then, upon
returning home, he set up two pendulums of equal length and swung one in larger, one in    smaller sweeps. They kept together and he found he was correct.
(In later experiments, Galileo was to find that the difficulty of accurately measuring
small intervals of time was his greatest problem. He had to continue using his pulse, or
to use the rate at which water trickled through a small orifice and accumulated in a
receiver. It is ironic then, that after Galileo's death the Dutch physicist and astronomer,   Christiaan Huygens was to use the principle of the pendulum, discovered by Galileo,as
the means by which to regulate a clock, thus solving the problem Galileo himself could
not. ¹

His observations led to Galileo's development of  the theory of isochronism of
the pendulum.  It was that theory that he used some fifty years later in the construction   of an astronomical clock.   For some insight into Galileo's pendulum experiments, go to   this site where students at Rice University repeat the same experiments.

¹Professor Fred L. Wilson, HISTORY OF SCIENCE:  Galileo and the Rise of Mechanism,
http://www.rit.edu/~flwstv/galileo.html
FLWGSH@ritvax.isc.rit.edu

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