Calculate density the old school way, measuring the net force acting on a submerged object.

• Compare the densities of two objects - one regularly shaped, and one irregular
• Measure volume by the displacement method
• Measure net force on the submerged object using a spring scale

Most of us have heard the apocryphal story of Archimedes running through the streets of Syracuse, but few actually understand Archimedes' Principle, that the buoyant force on an object submerged in a fluid is equal to the weight of the fluid that is displaced by that object.

This simple kit can be used to calculate the density of an irregularly shaped object. Using a spring scale and an overflow displacement vessel, students can calculate the bouyant force of two objects submersed in water. A couple of free body diagrams, and a sum of forces later, and physics students can calculate and compare the densities of the objects. Eureka!