A pendulum is a weight suspended from a pivot so that it can swing freely. ... When released, the restoring force acting on the pendulum's mass causes it to oscillate about the equilibrium position, swinging back and forth.

What affects the oscillation of a pendulum?

The only factor that significantly affects the swing of a pendulum on Earth is the length of its string. ... The length of the string affects the pendulum's period such that the longer the length of the string, the longer the pendulum's period.

How does a pendulum keep oscillating?

(A pendulum is loosely defined as something hanging from a fixed point which, when pulled back and released, is free to swing down by gravity and then out and up because of its inertia, or tendency to stay in motion.)