Maxwell’s Vibration Needle – Graduated is a high-precision physics laboratory apparatus used for determining the modulus of rigidity of a wire by the dynamical method. It is designed to provide accurate observation of torsional oscillations and variation in moment of inertia during the experiment.

The apparatus consists of a hollow brass tube of approximately 40 cm length and 18 mm diameter. It is supplied with two solid brass cylinders and two hollow brass cylinders, which can be arranged in different positions to change the moment of inertia. The tube is graduated from 0 to 15 cm on both sides and fitted with a Vernier scale for fine readings up to 0.05 mm.

 A centrally fitted pin-vice ensures proper suspension of the wire, while the attached plane mirror helps in accurate observation and counting of oscillations. Supplied complete with a wall bracket, this apparatus is ideal for advanced elasticity experiments in schools, colleges, universities, and engineering physics laboratories.

 Experimental Objectives

 To determine the modulus of rigidity of a given wire by the dynamical method.
To study torsional oscillations using Maxwell’s vibration needle.
To observe the effect of changing moment of inertia on the time period of oscillation.
To understand the elastic behavior of wire under torsional conditions.