The aim of this "Science Note" is to describe how to test the electron-sea model to determine whether it accurately predicts relative electrical conductivity for first-row transition metals. In the electron-sea model, a metal crystal is viewed as a three-dimensional array of metal cations immersed in a sea of delocalised valence electrons that are free to move throughout the crystal (Figure 1). This simple model obviously ignores the different lattice structures found in metals. This would be a suitable exercise for gifted and talented students in chemistry or those preparing for the International Chemistry Olympiad. (Contains 1 table and 3 figures.)