Exploring Friction with the Ancient Egyptians

Abstract

We devised an activity to explore friction by testing some of the common theories on how ancient Egyptians moved the stones used to build the pyramids. The activity is suitable for a high school physics course or introductory college courses for both science majors and non-science majors. The students investigate dragging a 1-kg mass (representing a stone) on a small wooden sled under three conditions: over dry sand, using wooden rollers over dry sand, and over wet sand. This last condition has been recently proposed as a potential method used by the Egyptians. The force required to pull the sled at a constant velocity is measured and used to calculate the kinetic coefficient of friction for each of the three test conditions. Students then perform a similar activity pulling their professor across a sand volleyball court. Versions of this experiment have been done in four classes of science majors (general physics, two 2-hour lab periods) and in four classes of non-science majors (physical sciences for educators, one 2-hour lab period).