Principle:

Two small lead balls of equal mass are positioned one at each end of a beam which is held suspended by a thin tungsten thread, so that it can swing freely across its equilibrium position. When two further, but larger, lead balls held on a swivel arm are now brought near to the small lead balls, forces of attraction resulting from gravitation effect acceleration of the small balls in the direction of the larger balls. At the same time, the twisted metal thread generates a restoring moment of rotation, so that the beam is subjected to damped oscillation across a new equilibrium position. The gravitational constant can be determined both from the difference in the angle of rotation of the different equilibrium positions and from the dynamic behavior of the swinging system during attraction. An integrated capacitive sensor produces a direct voltage that is proportional to the angle of deflection. This can be recorded over time by an interface system, and the value of the angle of rotation that is required be so determined.

Tasks:

1. Calibrate the voltage of the capacitive angle sensor.

2. Determine the time of oscillation and the damping of the freely swinging torsion pendulum.

3. Determine the gravitational constant, using either the acceleration method, the final deflection
method or the resonance method.

What you need:

Cavendish-balance, computerized 02540.00 1
Data cable 2 x SUB-D, plug/socket, 9 pole 14602.00 1
Circular level with mounting, d = 35 mm 02122.00 1

Complete equipment set, Manual on CD-ROM