A laboratory experiment often performed in an introductory electricity and magnetism course involves the mapping of equipotential lines on a conductive sheet between two objects at different potentials. In this article, we describe how we have expanded this experiment so that it can be used to illustrate the electrostatic properties of conductors. Different configurations of electrodes can be used to show that the electric field is zero inside a conductor as well as within a cavity, the electric field is perpendicular to conducting surfaces, and the charge distribution on conducting surfaces can vary.

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When students perform the experiment, they usually draw the equipotentials and field lines using pencil. For ease of viewing, we have traced over the pencil marks using a silver marker for the equipotentials and a green paint pen for the electric field lines in Figs. 2 to 4, which depict the configurations utilized by students in their investigation.
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