This article reviews Archimedes’ principle and elaborates on the idea with three fully solved examples. The reader is encouraged to attempt the problems on their own before checking the solution.

Consider a container of fluid at rest, as shown in the figure below. Since the fluid is at rest the net force on any part of the fluid is zero. Let us draw an imaginary boundary around some region of the fluid, as shown in the figure. This parcel of fluid has a weight , where is the density of the fluid and is the volume of the parcel. …