Built for accurate torsion and elasticity experiments, the Torsion Apparatus – Searle’s Horizontal Type (100 cm, 3 Scales) is used to determine the modulus of rigidity of metallic rods by measuring angular deflection under applied torque.

The apparatus is designed with two cast iron V-shaped supports connected by support rods, with one rod graduated for convenient measurement. A 165 mm diameter ball-bearing mounted wheel fitted with a self-centering chuck holds one end of the test rod, while the other end is securely clamped to maintain proper alignment during experimentation.

Two adjustable pointers and three circular scales graduated 30°–0°–30° allow precise measurement of angular twist. The apparatus is supplied with one brass rod and one steel rod of approximately 55 cm length. Weights are not included.

 Experimental Objectives

To determine the modulus of rigidity of metallic rods using Searle’s horizontal torsion apparatus.
To study the angular deflection produced in a rod under applied torque.
To compare the rigidity of brass and steel rods.
To understand the relationship between torque, angle of twist, and modulus of rigidity.