Experiment 3 — The One-Second Pendulum

Topic: Physics · Classes 6–7 · Motion and time: the simple pendulum

Aim: Build a pendulum whose time period is exactly 1.00 second .

Daily: Pendulum clocks kept India’s railway time for a century, and a swinging temple bell or a child on a jhoola obeys exactly the same rule: only the length decides the rhythm.

Obs: The pendulum completed one full swing in

Question: You replace the light bob with a bob twice as heavy, keeping the length the same. The time period will…

Exp: The period of a simple pendulum depends on length, not on the mass of the bob.

Question: The time period of a pendulum depends on its…

Exp: T = 2π√(L/g): only length (and gravity) matter.

Question: To make the period longer you should…

Exp: A longer pendulum swings more slowly.

Question: Why time 20 swings instead of one?

Exp: Dividing the total by 20 shrinks the error twentyfold.

Question: One complete to-and-fro swing is called one…

Exp: Its duration is the time period.