School of Physics Lecture Demonstration Manual

Fa-1 Archimedes' principle - The Bucket and Cylinder experiment

Published: Thursday 16 February 2006 - Updated: Monday 28 March 2011


To demonstrate Archimedes' buoyancy principle.



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Fa-1 Pic



 a) Principle of Physics illustrated
 That a body wholly or partly immersed in a fluid is subject to a buoyancy force of magnitude equal to that of the weight of the displaced fluid.


A solid metal cylinder C and a cylindrical bucket B into which the cylinder just fits are suspended from a balance arm with the cylinder attached to a hook on the base of the bucket. Weights are added to the other balance pan until the balance arm is horizontal. The solid cylinder is then completely immersed in water by raising beaker A with the aid of the labjack. The buoyancy force on the immersed cylinder disturbs the equilibrium of the balance. Upon filling the bucket to the brim with water the balance is seen to be restored by the balance arm.

Safety notes

Sharps Safety 


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