3B Scientific U40205 Bedienungsanleitung Seite 10

1003337 / Cavendish Torsion Balance U40205
Operating instructions
04/10 ALF
The Cavendish torsion balance is for demonstrating the
gravitational attraction between two masses and
determining the gravitational constant.
The key component of the torsion balance is a torsional
pendulum, consisting of a supporting beam suspended
horizontally from a thin tungsten wire and bearing two
small lead spheres. The apparatus is moved from its
equilibrium position by the gravitational force exerted
on the two small spheres by two larger spheres. If the
larger spheres are moved, the torsion balance will be
drawn out of equilibrium and will oscillate around the
new equilibrium position. The motion itself can be
measured using a
1. Description
capacitive differential sensor, which largely suppresses
the noise and vibration from the signal, and displayed
on a computer. To evaluate the results further, the data
can be exported
Alternatively, the movement can be demonstrated with
the help of a laser pointer.
Thanks to the short period of oscillation, between 2
and 4 minutes depending on the length of the
tungsten wire, the gravitational constant can be
measured within the time span of a school lesson to
an accuracy better than 10%.
1
to a spreadsheet program.