Gravitation Torsion Balance

A precision apparatus for demonstrating the gravitational attraction between two masses and determining the gravitational constant G. A torsion body carrying two small lead balls and a mirror hangs from a bronze torsion wire inside a windowed housing that shields it from draughts; the housing mounts on a stand rod with a holder for the large lead balls that deflect the torsion system. The deflection is read either as a laser spot on a distant scale or with an IR position detector, and two self-adhesive scales and the large lead balls are supplied. Ideal for classical-mechanics and gravitation courses, it lets pupils analyse oscillation, equilibrium states and very small forces. This is a special-order item with a delivery time of 10–12 weeks; the torsion wire is available as spare part no. 198055.