For proving Hookeâs Law of Elasticity, i.e. that elongation of an object is directly proportional to the load applied and demonstrating the phenomenon of simple harmonic motion of a vibrating weight, potential energy etc. Consists of an adjustable mirrored scale 15cm long, graduated in millimeters, mounted on a support rod 30cm long ï¬tted on a base. A hook attached to the rod supports a spring and indicator. Provided with a 50g brass hanger. Required slotted weights can be ordered separately.