The torsion pendulum is an interesting example of simple harmonic motion, often overlooked by students. It is helpful in explaining the meaning of moment of inertia and moment of torsion and how they affect the period of vibration. The one end of suspension wire hangs from a Universal Clamp with the help of a chuck nut and the other end is clamped to a solid brass disc of 12.5cm dia and 1.25cm thick with the help of a chuck nut. A heavy metal ring of the same metal (brass) and the same outside diameter as the disc is included. When ring is placed on the disc, the moment of inertia, and therefore the period of vibration of the system, is Increased.