Like Charges Attract

A soda can is charged negatively using the cat fur/teflon rod. When an oppositely charged rod (ebonite/plastic) is brought near, the can begins to roll towards the rod as expected. However, when the teflon rod is brought near, the can still rolls towards the rod. This is due to the electrically conductive nature of the can. The rod will repel the charges that were placed on the can and create a positively charged environment on the near surface. So even though the can is net negative, the induced dipole that is created results in a net attraction and the can rolls towards the rod.