A teacher places a metal can on top of an insulating foam cup and touches the side of the foam cup with a negatively charged rod. The setup is shown in the picture below.
What will happen to the negatively charged electrons when the rod touches the foam cup?
When the negatively charged rod touches the foam cup, some of the negative charge will be transferred to the foam cup. This will cause the electrons in the metal can to be repelled and move away from the side of the foam cup that was touched by the rod. This will result in a redistribution of charge on the metal can, with more negative charge being concentrated on the side of the can opposite to where the rod touched the foam cup.
