When Galileo Galilei was just 19 years old, he was a medical student, but like all university students of his time, he was required to attend church services regularly. Despite attending mass, Galileo found the sermons dull and uninteresting, and his mind often wandered to the fascinating problems of science that captured his curiosity more. One day, he noticed a lamp hanging from the church ceiling swinging back and forth. It had likely been nudged while being lit, but what intrigued Galileo was that the lamp continued to swing for a long time and with a regular rhythm. He observed that although the swings gradually became smaller, the time it took for each swing remained almost the same. Curious, he used the beat of his own pulse to measure the timing and confirmed his observation.
