To measure the time period of the pendulum, we have to record the time the pendulum takes to complete [[1]] 

To measure the time period of the pendulum, we have to record the time the pendulum takes to complete one oscillation. To do so, the bob of the pendulum is displaced slightly from the mean position and then released. The pendulum moves back and forth about the mean position. The time periods of several oscillations are measured and an average value of all the time periods gives an approximate time period of the pendulum.