Assignment:
Part 1:
Questions:
A. What happened when you brought the rubbed ruler close to the paper, salt, and pepper?
1. Were all three substances affected equally?
2. What explanations can you offer for why this happened?
B. What combinations of cloth and ruler seemed to produce the greatest effects?
Part 2:
Questions:
A. Why do you think the charged ruler affected the original suspended strip as it did?
B. What happened when you brought the two separated tapes close to each other? What explanations can you offer for this?
C. How many types of charge did you work with in this activity? How do you know?
D. If a third type of charge existed, how would it affect the two oppositely charged strips in this activity?
E. Why do you think the charged ruler affected the two suspended tapes as it did?
F. How would you explain the attraction or repulsion between each of the suspended tapes and the uncharged paper strip?
G. How would you explain the fact that a charged ruler can attract an uncharged object like the paper bits, salt and pepper?
Part 3:
1. Recharge the second Styrofoam cup by rubbing it with the fur. Run the cup lightly over the back of your arm. What do you observe and/or feel happening?
2. Bring the Styrofoam cup close to another person's hair. What do you observe? What conclusions can you make regarding charged Styrofoam?
Part 4:
1. Rub an inflated balloon with the fur and try to stick it to different surfaces. What can you make the balloon stick to? Does it stick better to some surfaces? Why?
2. Rub an inflated balloon against your hair and then try to stick it to the same objects you used for step A. Does rubbing with fur work as well as, better than, or worse than if you rub the balloon against your hair instead?
3. Bring the charged balloon close to the paper scraps from Part 2. How does the rubbed balloon affect the paper bits?
4. After rubbing a balloon with fur, bring the balloon near but NOT touching a very thin stream of water. Record your observations. Does the same thing happen when other charged objects are brought near the water? Try some and record the results. Be careful to NOT get the fur
wet!
Part 5:
A. Describe what you observed. "Why does this happen? Use appropriate diagrams to help you explain".
B. "What does this observation mean in terms of the charge on the ball and the ruler? "
- "Exactly what was the purpose of touching the ball while the ruler was nearby?
- "Draw appropriate diagrams to support your verbal descriptions. You should draw more than one illustrative diagram for this section."
C. Neutralize the aluminum foil ball. Bring the charged ruler close enough to the ball so that the ball gently and quickly touches it only once. Describe what you observe just after they touch. Explain why this happens in both words and appropriate diagrams.