SCIENTIFIC PRINCIPAL DEMONSTRATION
THE ROLLING SODA CAN

Materials:

Empty soda can, PVC pipe, wool cloth

Rub the PVC pipe vigorously with the wool cloth. Hold the charged PVC pipe next to an empty soda can laying on its side, parallel to the axis of the can. As the PVC pipe is slowly pulled away, the can will roll along the table, following the pipe.

Charges in the can feel electric forces from the charged pipe so that closest side of the can becomes charged opposite to the charge on the pipe. Because of friction between the can and tabletop, the can cannot slide towards the pipe. It is round, however, so the attractive electrical force causes the can to roll.

While electrical forces and friction are too advanced for this grade level, the notion that a force causes the motion of an object to change can be explored.