Introducing Archie – A Useful Tool for Teaching Archimedes’ Principle

Archimedes’ principle has been and still is a complicated concept to understand by introductory students, especially as typically stated in physics textbooks. Take for example its statement by Bierman: “When a body is fully or partially submerged in a fluid, a buoyant force from the surrounding fluid acts on the body. The force is directed upward and has a magnitude equal to the weight of the fluid that has been displaced by the body.” The principle may seem confusing to some students when introduced using the variation of pressure between the top and bottom of an object. Such students “cannot apply Archimedes’ principle even in very simple situations.” For this reason, a 3D-printed instrument, Archie, was developed that can be used to help with the introduction of Archimedes’ principle using simple experiments and observations. This article offers an introductory description and sample measurements showing how Archie works in practice.