Determination of the gravitational constant/ computerised Cavendish balance
Principle
Two small lead spheres are positioned on a beam, which is freely suspended on a thin metal wire. At the beginning the large lead spheres are positioned symmetrically opposite to the small spheres in that way that the attractive forces are eliminated. There after, the large spheres are swung so that they are close to the small spheres. As a consequence of the gravitational attracting force the beam with the small spheres now moves in a new equilibrium position, where the attractive forces are equivalent to the force of the torsion of the wire. The gravitational constant can be determined from the new equilibrium position.
Benefits
- Compact system
- Simple and quick set-up
- Basic constant in physics easily determined
- Data logging via USB
Circular level, d = 36 mm
Cavendish balance/computerized
Tasks
- Calibration of an angular detector.
- Determination of the oscillation time of a free and damped oscillating torsion pendulum.
- Determination of the gravitational constant.
What you can learn about
- Law of gravitation
- Free, damped, forced and torsional oscillations
- Moment of inertia of spheres and rods
- Steiner’s theorem
- Shear modulus