Question

To measure the pendulum why is it advisable to measure time of 20 oscillations and then calculate time of one oscillation, instead of simply measuring 1 oscillation by the stop watch

Answer 1

Answer:

The short answer is to reduce the uncertainty in your measurement of the period. ... If you are using a stopwatch and manual timing- then your uncertainty in timing an interval is likeley to be about say 0.2 s . If the period of the pendulum is about 1 second then 0.2 s uncertainty corresponds to about 20% .