The Floating Egg Problem

This is the grown-up version of the classic "float an egg in salt water" experience, plus an experiment in soap making. High schoolers explore density, but more importantly, practice accuracy, precision, and the use of significant figures in the laboratory. Using a different volume measurement devices, they determine the density of a solution for making soap. Sodium chloride is substituted for lye, so this can be done with beginning chemists early in the course.