to DMG-Lib main page
Home  · Site map  · Contact  ·

Advanced Search   Mechanism Search

Hydrostatic balance

Click to enlarge

Structure of mechanism

Function This instrument comprises a horizontal beam, which oscillates on a knife-edge which is in fact a steel prism. This knife-edge is part of the beam. At each extremity of the beam is another knife-edge (facing upwards) on which is suspended a staple supporting two pans. Each pan is equipped with a hook from which objects can be suspended before being immersed in a liquid. Two nuts on threaded shafts enable the balance adjustment of the mobile parts. A very long needle fixed to the middle of the beam, facing downwards, moves in front of a very small graduated rule to facilitate the monitoring of the equilibrium. On the front of the apparatus there is also a screw, which is used to raise or lower the beam with respect to the knife-edge fulcrum. This avoids unnecessary wear when the scale is not in use. The supporting column is fixed to a tripod, which features a spirit level on one of its legs.


Examples of application This scale enables the demonstration that Archimedes’ thrust, which acts on an object immersed in a liquid, is equal to the weight of the liquid displaced. The principle consists of attaching an object, immersing it in a recipient filled with water, and determining the weight by bringing the beam’s needle back into the vertical position by adding weights to the other pan.
It was used by future teachers during their studies at the men’s and women’s teacher training colleges, now the IUFM (University Teacher Training Institute) in Clermont-Ferrand.
Permanent links
DMG-Lib FaviconDMG-Lib
Europeana FaviconEuropeana
Data provider
Further media formats

nach oben up