Wad up a piece of aluminum foil into a loose ball about an inch or 3 cm in diameter, and gently attach a string or thread with a small piece of tape to it. Use a string long enough to attach the other end to allow the ball to hang freely at a convenient level and sufficiently away from any object. The bottom of a high shelf or the bottom of high kitchen cabinet might work. Using the best charging combination you found above, bring the charged plastic close to but not touching the aluminum ball. 4. What do you observe? Explain what charging method is effecting the aluminum.
5. Next, allow the charged plastic to briefly touch the aluminum. Bring the plastic relatively close to the aluminum again without touching it. Explain what you are observing.
Touch the aluminum with your finger to neutralize it, and recharge the plastic. Again bring the plastic close but do not touch the aluminum. While holding that pose, gently touch the opposite side of the aluminum with your finger, then remove your finger, then remove the plastic.
6. If you bring the plastic back to the aluminum without touching it, does it seem to attract more or less than before?
7. Compared to the charge on the plastic, how is the aluminum now charged?
8. What is the purpose for touching the aluminum with your finger during this procedure? Suppose the plastic was charged negatively. What type of charge flowed threw your finger and in what direction?
Now take your charged plastic and bring it close to a thin stream of water from a faucet.
9. What do you observe happening to the water? What is happening to the individual water molecules to make this happen?