NOTES: Currently, the physical science and physics lab are identical.
This lab takes about 1 hr.
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Static Electricity
Objectives:
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Observe how static electricity is generated
PART 1: Balloons
Procedure:
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Go to: http://phet.colorado.edu/en/simulation/balloons
Click “Run”
Rub the balloon on the sweater a little
Move the balloon halfway to the wall and let go
1. What is the sign of the charge on the balloon?
2. What is the sign of the charge on the sweater?
3. What side of the balloon does the charge stay on? Why?
4. Why don’t positive charges ever leave the sweater?
5. If each blue ball represents an electron, compare the number of electrons that are added to the balloon to the number
of electrons that are removed from the sweater.
6. What happens to the charge in the wall when you bring the balloon close to it?
7. Figure A is a picture of charges after the balloon has been rubbed on the sweater and stuck to the wall. On Figure B,
draw the NET CHARGES on the sweater and wall. Draw + signs on regions with a positive net charge and – signs in
regions with negative net charge. Draw nothing where the net charge is zero.
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8. Why does the balloon stick to the wall?
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Find the point where the balloon goes to the wall instead of the sweater
Rub more charge on the balloon.
Find the point where the balloon goes to the wall instead of the sweater
Rub all the charge from the sweater on to the balloon.
Find the point where the balloon goes to the wall instead of the sweater
9. How is the point where the balloon will go to the wall instead of the sweater affected by the amount of charge on the
balloon?
10. When you bring the balloon near the wall, how does the movement of charge in the wall change as more charge is
added to the balloon?
PART 2: John Travolta
Procedure:
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Go to: http://phet.colorado.edu/en/simulation/travoltage
Click “Run”
Put John’s finger close to the door nob
Rub John’s foot until there is a spark
Repeat at with John’s finger at several distances from the nob and count the number of rubs it takes
Distance between
finger and nob
Close
Medium
Far
# of rubs to
get spark
11. What do the little blue dots in John’s body represent?
12. Can you tell whether the charge on John is positive or negative?
13. How does the distance of the finger to the nob affect how many times John needs to rub his foot to get a spark?
14. The charge on the floor is not shown. What will it be when after John rubs his foot on the floor?
15. What is the charge on John after the spark?
Part 3: Pith Balls
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Open the Pith Ball Simulation. Read the instruction for the simulation.
http://physics.weber.edu/amiri/director/dcrfiles/electricity/pithBallS.dcr
 Bring the Rubber Rod near the pith ball without touching.
16. Note that no charge is added to or removed from the ball. Explain how the sides of the ball get charged.
17. The left side of the ball is charged positive. Does that mean that protons move to the left? Explain.
 Touch the Rubber Rod to the pith ball.
18. Is charge added the ball?
19. Explain how the subatomic particles move between the ball and the rod?
20. What type of charge transfer is taking place? Conduction, Induction, Friction?
21. Is the ball attracted to the rod or repelled or neither?
 Press the reset button. Change to the Glass rod. The glass rod is positive.
22. Bring the Glass Rod near the neutral pith ball. Explain how the sides of the ball get charged.
 Touch the Glass Rod to the pith ball.
23. Explain how the subatomic particles move between the ball and the rod?
Part 4: Electroscope
Open the Electroscope Simulations.
http://www.hinsdale86.org/staff/jliaw/topics/Waves/EM/Electrostatics/sims/07%20Methods%20of%20Charging%20Elect
roscope/electroscope.html
24. The electroscope is neutral at the beginning. What does this mean?
25. Click on Charge Separation and press play. The rod is negative. What happens to the electrons in the scope?
26. What happens to the leaves of the scope as the rod is brought near the scope? Why?
27. Press the Backward Step button and observe what happens as the rod is removed from the scope. What happens to the
electrons in the scope as the rod is removed?
28. What happens to the leaves when the rod is removed?
29. Click the menu button. Select Charge by Conduction. Press Play. What happens to the scope when the rod touches?
30. What happens to the leaves of the scope after the rod touches the scope? Why?
31. What charge does the scope have after the rod is removed?
32. What happens to the leaves of the scope after the rod is removed?
Challenge Section:
33. Click the menu button. Select Charge by Induction. Press Forward Step. The rod moves towards the scope without
touching. What happens to the electrons in the scope?
34. The scope is now grounded. What happens to the electrons?
35. The ground is removed and then the rod is removed. What happens to the electrons in the scope?
36. What is the charge of the scope?
37. What happens to the leaves of the scope after the process of induction takes place?
Part 5: Losing Charge
Open the Losing Charge animation. Read the paragraph.
http://www.regentsprep.org/Regents/physics/phys03/atheft/default.htm
38. How does a charged object lose its charge to the atmosphere if it is negative like in the animation?
39. The same thing occurs to a positively charged object. What must the particles in the air do to the positive object to
“steal” its charge?
Additional section (Not required)
Part 6: Lightning
Open the two Lightning Animations.
http://micro.magnet.fsu.edu/electromag/java/lightning/index.html
http://www.regentsprep.org/Regents/physics/phys03/alightnin/default.htm
Explain why lightening occurs.