A Cavendish torsion balance demonstrates the force of gravity between two masses and allows the gravitational constant to be determined. Thanks to the short oscillation period of just 2-4 minutes, the gravitational constant can be determined within the space of a single lesson with an accuracy of better than 10%.
The core of the apparatus is a torsion pendulum made of a light bar with two small lead spheres, which is suspended horizontally from a thin wire. The apparatus is moved from its rest position by the attraction of the two spheres to two larger lead spheres. When the two large spheres are rotated to a new position, the torsion balance will vibrate about a new rest position. The rotary motion is measured using a capacitive differential sensor, which largely suppresses noise and vibration components in the signal. The output is then recorded using a computer. For subsequent evaluation, the data can be exported to a spreadsheet. Alternatively, the motion can be demonstrated with the aid of a light pointer.
Mass of large lead spheres: 1 kg
Mass of small lead spheres: 15 g
Gravitational attraction: < 10-9 N
Torsion wire: Tungsten, 25 µm
Period of oscillation: 2-4 mins
Angular resolution: 25 microradians
Sampling rate: 0.5, 1, 2, 5, 10 samples/s
Dimensions: 190 x 180 x 200 mm³
Weight: 5 kg
Includes:
1 Cavendish torsion balance
1 Measurement software
1 USB cable
The core of the apparatus is a torsion pendulum made of a light bar with two small lead spheres, which is suspended horizontally from a thin wire. The apparatus is moved from its rest position by the attraction of the two spheres to two larger lead spheres. When the two large spheres are rotated to a new position, the torsion balance will vibrate about a new rest position. The rotary motion is measured using a capacitive differential sensor, which largely suppresses noise and vibration components in the signal. The output is then recorded using a computer. For subsequent evaluation, the data can be exported to a spreadsheet. Alternatively, the motion can be demonstrated with the aid of a light pointer.
Mass of large lead spheres: 1 kg
Mass of small lead spheres: 15 g
Gravitational attraction: < 10-9 N
Torsion wire: Tungsten, 25 µm
Period of oscillation: 2-4 mins
Angular resolution: 25 microradians
Sampling rate: 0.5, 1, 2, 5, 10 samples/s
Dimensions: 190 x 180 x 200 mm³
Weight: 5 kg
Includes:
1 Cavendish torsion balance
1 Measurement software
1 USB cable
Properties
- 833490
- U40205