Measuring g using buoyancy: a simple and accurate method for high-school physics lab

Abstract This article presents a simple and accurate method for determining the gravitational acceleration g by applying Archimedes’ principle. A cylindrical aluminium rod was suspended and gradually immersed in water, and a digital scale recorded the buoyant force at each depth. The volume of the immersed rod was calculated geometrically with a correction applied to the finite vessel size. By plotting the buoyant force against volume and using the known density of water, the value of g was extracted from the slope of the best-fit line. The result, g = 9.788 ± 0.023 m s −2 , agreed well with the accepted value and demonstrated the educational potential of fluid-based alternatives to traditional kinematic methods. This experiment offers a low-cost and conceptually rich opportunity to explore hydrostatics, Newtonian mechanics, and metrology in an integrated manner. As such, it represents a valuable and accessible method for high school physics laboratories.