Galileo was once bored as he sat through a church service. His mind wandered and noticed a chandelier’s repeated movement as it hung from the ceiling. He noticed that the chandelier swung from its center and stationary position, and no matter how far it swung, whether 5 inches or a foot, it still took the same amount of time (measured by his own pulse) to complete a full swing. That is, it took same number of heartbeats to complete its cycle from one extreme of the swing to the other. Thus, the pendulum was discovered to be an accurate tool in timekeeping, and paved the way for mantel clocks.