Description
Unformatted Attachment Preview
Purchase answer to see full attachment
Explanation & Answer
Here's the file, let me know if you want me to edit it at all
Name: ______ Group Member_________________
Static Electricity
When certain types of material such as black vinyl rods, white vinyl strips, plastic combs, and latex
balloons are rubbed with cat’s fur, wool, or human hair, these objects become negatively charged. The
friction between the two materials (e.g. a balloon and your hair) causes electrons to be removed from the
protein molecules of the hair and attach themselves to the molecules of the latex balloon. The balloon
retains a net negative charge.
When glass rods or acetate strips are rubbed with a piece of silk or cotton, the electrons are stripped off
of the glass or acetate and the glass or acetate becomes positively charged.
Objective:
1. Students will do a series of activities to investigate the nature of static electric forces.
2. Students will recognize the properties of positive and negative charges.
Materials:
small, inflated balloon
a piece of wool cloth.
small bits of paper
two 20-cm pieces of string or thread
two 6 x 6-cm pieces of aluminum foil 铝片
Scotch Magic TapeTM
one coat hanger
salt
pepper
paper plate
Procedure:
1. Tear a small piece of paper into very tiny bits. Lay them on the table. Charge an inflated
balloon in your hair or with a piece of wool cloth. Slowly bring the balloon near (without
touching) the bits of paper.
2. Place one of the 20-cm pieces of string on one of the 6 x 6-cm pieces of aluminum foil.
Crumple the foil into a ball so the string is caught in the ball. Repeat this with the other
piece of foil and piece of string. Suspend the two foil spheres from a coat hanger.
Charge the balloon and slowly bring it up under the 2 spheres.
3. Move one sphere out of the way leaving only one sphere hanging. Bring the charged
balloon near the one hanging sphere. Do not let the balloon touch the sphere. Now let
the charged balloon touch the sphere.
4. With a partner, stick two 6-inch pieces of c tape together, sticky side to non-sticky side as
directed below….
a. Take two 15-cm pieces of Scotch Magic TapeTM and fold a 1-cm tab on both ends
of each piece of tape.
b. Stick one piece of tape to your desk. Write the letter “B” for “bottom piece” on
one of the tabs.
c. Stick the other piece of tape on top of the piece already on the table. Mark one of
these tabs with the letter “T” for “top piece”
d. You now have a “tape sandwich”.
e. Holding only the tab marked “B”, pull the “tape sandwich” off the table. Do this
very slowly.
f. At arms length hold the tab “T” between the finger and thumb of one hand and the
tab “B” between the finger and the thumb of the other hand. Quickly rip the two
pieces apart.
g. You now have two oppositely charged pieces of tape.
h. Slowly and carefully bring them near each other.
i. Record observations.
j. Using another pair of charged pieces of tape, compare two “B” pieces of tape.
k. Another tape has negative charges on the “B” pieces while this tape has positive
electrons on “B”.
l. Compare the two “T” pieces of tape.
m. The two “T” pieces both has the negative charges.
5. Start the water running from a faucet. Adjust the flow so as to produce a narrow, steady
stream (no dripping). Charge the balloon and bring it near the stream of water. Do not let
the balloon touch the stream of water.
Observations
Balloon and Pieces of Paper
The balloon attracted the pieces of paper.
Balloon and Two Aluminum Spheres
The two spheres are attracted to the balloon.
Balloon and One Aluminum Sphere
The one aluminum sphere was initially attracted to the balloon, and the closer I got with the
balloon, the closer the sphere stretched to meet the balloon. However, once I touched the balloon
to the sphere, the sphere started to be repelled by the balloon.
Balloon a...