Electricity: Static And Current
Catherine Coughlin Douglass Math and Science Academy
543 N Waller
Chicago IL 60644
(312) 534-6176
Objectives:
The students will be able to:
1. Explain that electrons are the things that make electricity work.
2. Name and define the two basic kinds of electricity as static and
current.
3. Compare conductors and insulators and explain how they are used.
4. Construct a battery to show the electrical flow in order to
demonstrate the proper use of electricity.
5. Develop an awareness of the potential hazard from improper use of
electrical appliances.
6. Develop an awareness of the potential danger from floods, fallen
power lines, etc.
Materials needed:
CLASS DEMONSTRATION:
1. Ring and ring stand 16. Battery operated toy
2. Glass beaker 17. Two potato clock
3. Pointer 18. 2 potatoes
4. Nylon string (approx. 4 feet) 19. 1-1.2 volt bulb
5. 2 balloons 20. 1-E10 bulb base
6. Pieces of wool and silk 21. 1-6 volt buzzer
7. Set of red and black wires 22. 1 Deli style pickle
with alligator clips 23. Old electric cord with plug on
8. 3-8"x 12" sheets yellow paper one end and other end split (cut
9. plastic wrap off socket) and taped, allowing
10. 1-8"x 12" sheet orange paper 1" of bare wire at both terminals
11. Rope (approx. 8 feet) 24. Distilled and tap water
12. Tape 25. Hydrochloric acid (HCl)
13. Variety of batteries 26. 2 graphite rods or pencils with
14. 6 volt lantern battery wood removed to expose lead
15. Flash light with batteries
GROUP ACTIVITIES (per group of 3 to 5 students):
1. 2 newspaper strips (1"wide x 14. Small paper cup distilled water
20" long) 15. Small paper cup distilled water
2. Piece of plastic wrap with sugar
3. Piece of aluminum foil 16. Small paper cup distilled water
4. 1 pencil with salt
5. 1 penny 17. Small paper cup vinegar
6. Piece of paper 18. Conductivity tester
7. 1 glass rod 19. 1 Digital multimeter
8. 1 plastic rod 20. Set of red and black wires with
9. 1 plastic toy alligator clips
10. 1 paper clip 21. 1 dime and 1 penny
11. 1 rock 22. 1 lemon
12. 1 wooden yardstick or ruler 23. 1 orange
13. Small paper cup tap water 24. 1 tomato
25. 1 grapefruit
Strategy:
INTRODUCTION:
Review previous lesson about basic structure of an atom being comprised of
protons, neutrons, and electrons. Explain that electrons are the things that
make electricity work. That sometimes an electron goes flying off one atom and
joins another. Describe first kind of basic electricity as static and define it
for students.
DEMONSTRATION #1: BREAKING UP A FRIENDSHIP BETWEEN 2 BALLOONS
Display a ring and ring stand with a pointer tied to the ring holder. Take
the 2 inflated balloons and tie 1 to either end of the nylon string. Hang this
from the pointer. Ask the students to observe how the balloons are hanging "at
rest". Rub 1 balloon with a piece of wool and the other balloon with a piece of
silk. Observe and discuss results. (The balloons will repel each other and fly
apart.) Rubbing the balloons charges each with the same negative charge.
Display picture you made on yellow paper which shows 2 electrons with the same
negative charge repelling each other. Tell students that repel mean to push
away just like the balloons.
DEMONSTRATION #2: BRINGING TWO BALLOONS BACK TOGETHER
Follow same procedure as above only this time rub balloons with wool and
plastic wrap. This time the balloons will be strongly attracted to each other
and will touch. Put up picture you made on orange construction paper showing
two electrons with different charges being attracted to each other. Tell
students that attract means to want to be close together.
GROUP ACTIVITY #1: LIKE CHARGES REPEL
Distribute 2 newspaper strips to each group. Hold them at one end and let
them hang. Stroke several times lengthwise from top to bottom with thumb and
forefinger. They will fly apart. Prompt students to say that same charges
repel. Stroke again using a piece of plastic wrap. This should produce greater
negative charges faster, and show a more dramatic repulsion. Again elicit from
students that these strips have the same charge and therefore repel each other.
DEMONSTRATION #3: NEGATIVE ELECTRON TRAIN
Have 6 to 8 students stand in a line at the front of the room. Tape a
small piece of yellow paper displaying a negative electron to each student's
arm. Have them carry a rope which represents the wiring and gently push each
other on the back causing them to move around the room. They are the electrons
pushing each other through a wire.
GROUP ACTIVITY # 2: LET'S FIND GOOD CONDUCTORS
Distribute worksheet to each student. Take turns reading list of items.
Explain to students about conductors and insulators. Show them each item listed
and how to test using Conductivity Tester. They should record results on
worksheet. Draw out from them the kinds of things that were conductors and
insulators.
GROUP ACTIVITY # 3: MAKING NATURE'S BATTERIES
A. Display a variety of batteries and things powered by batteries. Show
the "Two Potato Clock". Ask the students how the clock is working. When they
tell you the potatoes are powering it, explain that they are going to test other
fruits and vegetables. Show the assembled Digital Multimeter and how to use it.
Complete test and record results. Ask what must be happening. Draw out
response that negative electrons must be moving freely.
B. Try to link up several lemons in a circuit, to see if they can light up
a 1.2 volt bulb. How many lemons were required to get the bulb to light?
DEMONSTRATION #4: SAFETY
Lead discussion on the possible dangers from electricity.
A. Attach ends of old electric cord to a pickle and plug in to socket.
Observe and discuss results. This is very dramatic! The pickle burns, glows
and smells but is also very dangerous. Make certain that students understand
that they are never to try this themselves.
B. Continue discussion of the hazards. Ask why we should never use
electrical appliances in bath or shower. Ask why we shouldn't go into a flooded
basement. Set up display of Electrolysis of Water. First attach wires to a 6
volt buzzer and/or the 1.2 volt bulb. Electricity is flowing from the 6 volt
battery through the wires, through the graphite rods and liquid, making a
complete circuit. Remove the bulb and/or buzzer and reconnect the wires.
Bubbles will begin to form on the rods proving that the electricity is flowing.
Point out that if the graphite rods were two legs, the person would be
electrocuted.
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