An electroscope is a device made of a metal ball connected through a wire to two aluminum plates that are suspended inside a glass flask. A student generates electrostatic energy by rubbing a plastic rod with a dry cloth. After a while, the student measures a positive charge on the cloth. Then, the student holds the plastic rod near the ball of the electroscope as shown in the diagram. Circle all of the areas where a negative charge has accumulated. cloth plastic rod wire aluminum plates Electroscope metal ball rubber stopper glass flask