The first scientific discoveries of Galileo happened when the year 2001 1584 when he was listening to the prayer in the church. One 
.He noticed a hanging lamp on the ceiling church you free to you free. He had some doubts that the sway of the lamp in each round take 
.Equal? Thus he was the timer oscillation of the lamp. By compared with the pulse of its own. Because he was studying medicine. He knew that the rhythm of the pulse of time spent in each equal.But the period of swing to and fully 1 cycles are always the same, when he go home ทำการทดลอง same several 
.Times to ensure that the theory that he set up the most accurate. The outcome of the trial is the same every time. Galileo named this theory that 
.The rules pendulum (Pendulum) or the swing of the pendulum clocks. Rules Galileo, the principle of experiment to create a timer 
, which later in the year. 1656 Christian. ฮฮย Gaines (Christian Huygens). The theory is to build the pendulum clock 
.