Dr. M. H. Suckley & Mr. P. A. Klozik
Email: MAP@ScienceScene.com
Visit our Website: http://www.ScienceScene.com (The MAPs Co.)
I. Static Electricity
II. Current Electricity
III. Applications
Electricity
I. Static Electricity
A. Teaching Static Electricity - Naive Ideas
B. Wonderment of Producing Static Charge
1. Rubbing
a. The Fluttering Butterfly . . . . . . . . . . . . . . . . . . . . . . . 5
b. The Static Mystery
......................... 6
2. Contact
a. Fickle Friends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
b. The Repulsive Ball
......................... 8
3. Induction
a. Dancing Spheres in Captivity . . . . . . . . . . . . . . . . . . 9
b. The Attractive Yard Stick, Broom, and 2 X 4’s. . . . 10
Electricity
I. Static Electricity
C. Explanations - Developing A Model
1. How Do Materials Become Charged?. . . . . . . . . . . . . . . . . . . . 11
2. Using The Model To Illustrate the Static Charge? . . . . . . . . . 12
3. Developing the Laws of Static Electricity
a. Golf Tubs and Test Tubes. . . . . . . . . . . . . . . . . . . . . . . . . . . 13
b. Sticky Tape Static Charges . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4. The Electrostatic Series. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
a. Where Should We Put Scotch Tape In The Series?. . . . . . . . 16
b. Attractive Stuff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
D. Applying the "Model" For Static Electricity
1. The Moving Soda Can, Ping Pong Ball, or Loony Loop. . . . . . 18
2. Groovy Record. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3. Electrophorus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4. Electrostatic Doorbell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5. The Van De Graff Generator
6. Static Charges Can Kill You
Electricity
II. Flowing or Current Electricity
A. Teaching Current Electricity - Naive Ideas . . . . . . . . . . . . . 22
B. Wonderment of Current Electricity. . . . . . . . . . . . . . . . . . . .
Static – Alternating and Direct Electricity
C. Building The "Simply Super" Circuit Board . . . . . . . . . . . 23
D. Parallel Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
E. Series Circuits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
F. Combined Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
G. Conductors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
H. Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
I. Diodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
J. Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Electricity
III. Application of Electricity
A. Buzzer Door Bell
B. Chime Door Bell
C. Speaker
D. Christmas Lights
E. Toaster
F. Light Bulb
G. Hair Dryer
We Had A Great Time
Acceptance of a New Concept
A widely accepted way to explain how learners adopt new understandings
of phenomena is presented in the Conceptual Change Model (CCM)*.
There are two major components to the Conceptual
Change Model.
The first component are the conditions that need to be met in order for
a person to adopt a new understanding. There are three conditions leading
to the adoption of a new concept. A learner has to:
(1) become dissatisfied with their existing concept,
(2) find the new concept intelligible,
(3) find the new concept plausible and fruitful.
The second component of the CCM is described as the status of the new
concept. A concept has status when it meets any of the conditions
indicated; however, the more conditions that the new concept meets, the
higher the status the new concept obtains, and hence, a higher probability
of being adopted.
References
7
*Posner, G.J., K.A. Strike, P.W. Hewson, and W.A. Gertzog. 1982. Accommodation of a
scientific conception: Toward a theory of conceptual change. Science Education 66: 211-27.
NSTA Board Adopts New Position Statement on Laboratory Science
The NSTA Board of Directors has adopted a new position statement which reaffirms the
central role laboratory investigations play in quality science instruction. “for science to
be taught properly and effectively, labs must be an integral part of the
science curriculum.” The new statement replaces Laboratory Science, which was
adopted in 1990.
Static Electricity
I. Naïve Ideas
1. After a material acquires a positive charge, it has more positive charges (protons) than
it did.
2. When a material has positive charge, the missing negative charges (electrons) have
been destroyed.
3. Whenever a material becomes charged, the charges have been newly created in the
process.
4. Positively charged atoms give a positive charge; negatively charged atoms give a
negative charge.
5. Static electric forces are always attractive.
6. In order for an object to act like it is charged, electrons must be added or removed.
7. All wires must be coated with an insulating material or the electricity will leak out.
7
Grade Level Appropriate Concepts
K-4:
Pushing or pulling can change the position and motion of
objects. (Electric forces can be used as a source of the push
or pull). Students will indicate that magnetism, gravity and
electrical charge can exert forces on objects without
touching the objects.
2
Grade Level Appropriate Concepts
5-8:
Unbalanced forces cause changes in an object’s motion. (An
imbalance in charges on an object results in an unbalanced
force, causing nearby uncharged objects to be attracted).
Students will recognize different forces and describe their
effects as magnetic, gravitational, electrical or nuclear forces
1
Grade Level Appropriate Concepts
9-12: The electric force is a universal force that exists between any
two charged objects. Opposite charges attract while like
charges repel. The strength of the force is proportional to the
charges and, as with gravitation, inversely proportional to the
square of the distance between them. Between any two
charged particles, electric force is vastly greater than the
gravitational force. Most observable forces such as those
exerted by a coiled spring or friction may be traced to electric
forces acting between atoms and molecules. Students will
identify the characteristics and relative strengths of magnetic,
gravitational, electrical and nuclear forces. Then they will
analyze the relationship between them.
0
Rubbing - The Fluttering Butterfly
Rubbing - The Static Mystery
1
2
Contact - The Fickle Friends
Contact - The Repulsive Ball
Induction - Dancing Spheres In Captivity
Induction - The Attractive Yard Stick, and 2 X 4
Models - How Materials Become Charged
OR Learning to Classify based upon Physical Properties
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3
Contact
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Induction
Models - How Materials Become Charged
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After Rubbing one Material has more and the other has fewer electrons.
2
2
Models - How Materials Become Charged
Contact
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Models - How Materials Become Charged
Induction
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When a material with an excess of electrons is moved near a material
without an excess of electrons the electrons within the uncharged material
move producing charged areas. When the material with an excess of
electrons is removed the electrons return to their original positions
0
Developing The Laws Of Static Electricity
Golf Tubes and Test Tubes
Developing The Laws Of Static Electricity
Sticky Tape Static Charges
Electrostatic Series
Materials tend to gain electrons and become
Negatively Charged
Materials tend to lose electrons and become
Positively Charged
Hard Rubber
Comb
Vinyl (PVC) - Golf Tube
Rubber Balloon
Plastic
Polyethylene
Reynolds or Saran Wrap
Styrene
Amber
Lucite
Wood
Steel
Cotton
Paper
Silk
Cat’s Fur
Wool
Nylon
Human hair
Glass
Rabbit’s Fur
Electrostatic Series
Where Should We Put Scotch Tape In The Series?
Substance
Transparency
Comb
Rubber Balloon
Plastic
Wood
Cotton
Paper
Silk
Wool
Nylon
Glass
Does the Scotch Tape
Attract or Repel?
Charge On:
Tape
Substance
Models - Electrostatic Series
Attractive Stuff
Applying the "Model" For Static Electricity
The Moving Soda Can
Attractive Ping Pong Ball
Loony Loop
2
Applying the "Model" For Static Electricity
Groovy Record
1
Lightning Rods
Lightning rods were originally developed by Benjamin
Franklin. A lightning rod is very simple -- it's a pointed
metal rod attached to the roof of a building. It connects to
a piece of copper or aluminum wire that's connected to the
ground.
The lightning rod provides a low-resistance path to ground
that can be used to conduct the enormous electrical
currents when lightning strikes occur.
0
Applying the "Model" For Static Electricity
Electrophorus \i-lek-'traf--rs\
2. Rub the Styrofoam with the wool.
3. Lower the cake pan NEAR the Styrofoam sheet.
4. Touch the cake pan with your fingertip.
5. Lift the cake pan away from the sheet.
6. Touch the cake pan again.
7. Repeat the procedure several times without rerubbing the sheet. You will obtain the same
results each time.
8. Repeat steps 2-5. Hold a neon bulb by one wire
and touch the other wire to the charged pan.
9. The filament, of the light bulb, that lights first
indicates the direction of the electron
movement, (negative to ground).
Applying the "Model" For Static Electricity
Static Electric Doorbell
Grounded
Insulated
Charged
Charged
Charged
Grounded
Insulated
Transparency
How a Van De Graff Works
2
Students and Van De Graff
1
Pie Pans and Van De Graff
0
Static Fires
Static electricity caused the fire that damaged this car. The Petroleum Institute has
researched 150 cases of these fires. Their suggestions indicate that you should
NEVER get back into your vehicle while filling it with gas. If you absolutely
HAVE to get in your vehicle while the gas is pumping, make sure you get out,
close the door and touch the metal, before you ever pull the nozzle out. This way
the static from your body will be discharged before you ever remove the nozzle.
Current Electricity
I. Naïve Ideas
1. Electrical energy flows from source to converter (light bulb, heater, etc.) by connecting
a single wire.
2. If two wires are needed, energy flows from the source to the converter through both
wires
3. In a circuit with electrical devices, more electrons leave the source than return to it.
4. Electrons are destroyed or “used by” the converter (light bulb, heater, appliance, etc.).
5. The electrons that comprise an electric current come from the source. (A dry cell is a
can full of electrons. When it is out of electrons, we throw it away or recharge it..)
6. Every part of a circuit gets the same current.
7. You can connect as many light bulbs, appliances, etc. in a circuit without affecting their
behavior.
8. To receive more light from a bulb, you need a different light bulb.
9. Adding batteries to a circuit always increases the current (brighter lamps, faster
motors, etc.).
10. All materials that conduct electricity conduct equally well.
11. Water is a good conductor. . . . . .
11
AC/DC Demonstrators
2
ALTERNATING CURRENT:
DIRECT CURRENT:
1
Direct and Alternating Current
No Current
Direct Current
Alternating Current - Blinking
Alternating Current – Solid light
0
3
Example Prices for Circuit Boards
Average Price of Commercially made Circuit Board
$84.00 - each
15934W2 Circuit Board $19.95
AP6302 Simple Circuits Kit
14718W2.
flashlight
AP6302
SimpleStandard
Circuits
Kit
$37.10bulb $3.25 Pk. Of 10
$37.10
Simple Circuits Kit
AP6302
Each for $43.05
Total Cost $21.00
4
Building the Simple Circuit Board - Materials
1. 7 - Magnets
2. 1 – Simple Circuit Card
3. 7 – Sticky Dots
4. 3 – Lamp Units
5. 12 – Paper Clip
6. 1 – Diode
7. 3 – 10 Ohm Resistors
8. Toothpick
9. Steel wool for Fuse
10. Red and Black Wire for
Battery Connection
10
The Power Supply
Polaroid
Polapulse
Battery
Polaroid
Polapulse
Battery
Polaroid
Polapulse
Battery
Polaroid
Polapulse
Battery
The power supply can be any 6-volt DC source. This could be 4 AA batteries, a
lantern battery or a transformer. We are using a battery pack obtained from a
Polaroid film pack.
Building the Simple Circuit Board - Battery
Step 1: Wrap wire onto paperclips making two leads
Step 2: Insert Paperclip Leads into Battery
Polaroid
Polapulse
Battery
Polaroid
Polapulse
Battery
Polaroid
Polapulse
Battery
Polaroid
Polapulse
Battery
Building the Simple Circuit Board –
The Simple Circuit Board
Parallel Circuit
Series Circuit
Combined Circuit
Building the Simple Circuit Board –
Circuit Board Lamps
Christmas Light bulb
Two Bent Paperclips
and Light Bulb
Bend Paperclip 90 Degrees
Heat Shrink Tubing
Wire Wrapped Around P.C.
Completed Lamp Unit
Multimeters
Amperage
Voltage
Building the Simple Circuit Board - Magnets
1. Place Glue Dot on Back of Magnet.
2. Place Magnet on Circuit Board.
1
Building the Simple Circuit Board –
Completed Parallel Circuit
1. Place Paperclips as Indicated.
2. Attach Lamp Units.
3. Attach Power Supply.
Polaroid
Polapulse
Battery
Polaroid
Polapulse
Battery
3
Polaroid
Polapulse
Battery
Polaroid
Polapulse
Battery
Qualitative Characteristics of Electricity
1. Connect the battery and observe the lights. (number lit and brightness)
2. Describe the effect of moving bulb unit 1 just enough to break
the circuit of the rest of the bulbs.
3. Describe the effect of moving bulb unit 2 just enough to break
the circuit of the rest of the bulbs.
Quantative Characteristics of Electricity
1. Volts - Pressure that cause the current to flow. The potential
difference across a conductor in an electric field
2. Amperes - Rate of the current flow. One ampere is
approximately equivalent to 6.24150948×1018 electrons
moving past a boundary in one second.
3. Ohms - Resistance of the conductor (wire or hose) to the
flow. A device has a resistance of one ohm if one volt causes a
current of one ampere to flow.
4. Watts - Power produced due to the pressure
and the flow of the electrons.
4
Parallel Circuits - Obtaining Voltage Data
2a
1b- ---Master
1a
1b
3a
1a1b
3
Parallel Circuit – Voltage Data
Circuit Simulator
Placement of Meter
Voltage
1b – 1a
1 (1)
4.3
1b – 2b
2(1+2)
4.3
3(1+2+3)
4.3
1b – 3a
Master - 1a
3(1+2+3)
4.3
Pattern observed: Voltage is constant in parallel circuits
5
Parallel Circuit – Obtaining Amperage Data
Master - 1b
Bulb -- 1b
2b
Bulb
3
Bulb - 3b
Parallel Circuit - Data
Circuit Simulator
Ammeter Placement
Amperage
Bulb – 3b
1(3)
0.20
Bulb – 2b
1(2)
0.21
Bulb – 1b
1(1)
0.21
Master – 1a
3(1+2+3)
0.60
Pattern observed: Amperage is additive in parallel circuits
5
Series Circuit
1. Place Paperclips as Indicated.
2. Attach Lamp Units.
3. Attach Power Supply.
Polaroid
Polapulse
Battery
Polaroid
Polapulse
Battery
3
Polaroid
Polapulse
Battery
Polaroid
Polapulse
Battery
Series Circuits - Obtaining Voltage Data
1b – 2b
2
Series Circuit – Voltage Data
Circuit Simulator
Placement of Meter
1b – 1a
1(1)
1.6
2(1+2)
3.2
3(1+2+3)
4.8
1b – 2b
1b – 3a
Voltage
Pattern observed: Voltage is additive in Series circuits
3
Series Circuit – Obtaining Amperage Data
Master – 1b
3
Series Circuit – Amperage Data
Circuit Simulator
Placement of Meter
Amperage
Bulb – 3b 1(3)
.157
Bulb – 2b 1(2)
.156
Bulb – 1b 1(1)
.156
Master – 1b
3(1+2+3)
.156
Pattern observed: Amperage is constant in Series circuits
4
Completed Combined Circuit
+
+
1. Place Paperclips as Indicated.
2. Attach Lamp Units.
3. Attach Power Supply.
Series
Circuit
Parallel
Circuit
Polaroid
Polapulse
Battery
Polaroid
Polapulse
Battery
3
Polaroid
Polapulse
Battery
Polaroid
Polapulse
Battery
Combined Circuit - Obtaining Voltage Data
Master
–––3b
-2b
Master
3b
3a
1a2a
1b
1a
– Source
3a
Power
3
Combined Circuit – Voltage Data
Placement of Meter
Voltage
Circuit
1a – 1b
1(1)
4.9
Parallel
2a – 2b
2(2)
2.4
Series
3a – 3b
2(3)
2.4
Series
4.9
Combined
4.9
Combined
1b – 3a
(2+3)
Power Source (1+2+3)
Note that in series circuit the voltage is additive
(2.4+2.4 = 4.8) and in parallel circuits it is constant.
Therefore the circuit voltage would be 4.8.
5
Combined Circuit - Obtaining Amperage Data
Master – 1b
1b – 3a
3
Combined Circuit – Amperage Data
Placement of Meter
Amperage
Circuit
Bulb – 3a
1(3)
0.16
Series
Bulb – 2a
1(2)
0.16
Series
0.16
Series
0.27
Parallel
0.44
Combined
1b – 3a
2(2+3)
Bulb – 1b
1(1)
Master – 1b 3(1+2+3)
Remember in series circuits amperage is constant and in
parallel circuits it is additive.
5
Therefore if we add the amperage for the series circuit to
the amperage for the parallel circuit we should get the
amperage for the entire circuit. (0.16 + 0.27 = 0.43)
Conductors
1. Place Paperclips as Indicated.
2. Attach Lamp Unit.
3. Insert paperclips into indicated
solutions.
4. Attach Power Supply.
Red (2.5% NaCl)
Green ( 0.5% Sugar)
Blue (10.0% NaCl)
Clear (Distilled Water)
1
Fuses
1. Place Paperclips as Indicated.
2. Attach Lamp Unit.
3. Obtain a strand of steel wool and
place it as indicated.
4. Attach Power Supply.
Diodes
1. Place Paperclips as Indicated.
2. Attach Lamp Unit.
3. Insert Diode.
4. Attach Power Supply.
5. Note orientation of diode, end
marker, and switch the diode.
Resistors in Parallel
1. Place Paperclips as Indicated.
2. Attach Lamp Unit.
3. Insert resistors 1, 2 and 3 as
indicated.
4. Attach Power Supply.
We Had A Great Time
Buzzer Door Bell
http://www.howstuffworks.com/doorbell2.htm
In a buzzer door bell an electromagnet is used to
operate a self-interrupting circuit. One end of the
electromagnet is connected to one end of the
electrical circuit and the other end of the wire
connects to a metal contact adjacent to a moving
contact arm. When the electromagnet is turned off,
the free end of the arm rests against the contact point.
This forms a connection between that end of the wire
and the electrical circuit allowing the electricity to
flow through the electromagnet when the circuit is
closed. This causes the electromagnetic field to
attract the iron bar, which pulls the contact arm off
the stationary metal contact breaking the connection
so the electromagnet shuts off. Without a magnetic
field pulling it back, the contact arm snaps back into
position against the stationary contact reestablishing
the connection between the electromagnet and the
circuit, and the current can flow through it again. The
magnetic field draws the contact arm up, and the
process repeats itself as long as you hold down the
buzzer button.
Chime Door Bell
www.howstuffworks.com/doorbell3.htm
A chime doorbell uses a
electromagnet called a
solenoid. A solenoid is
just an electromagnet
where the coiled wire
surrounds a metal piston.
The piston contains
magnetically conductive
metal, so it can be moved
backward or forward by
the electromagnetic field.
Speaker
A speaker takes the electrical
signal and translates it into
physical vibrations to create
sound waves. Speakers do this by
rapidly vibrating a flexible
diaphragm or cone. One end of
the cone is connected to the voice
coil and the other end to the cone.
The coil is attached to the basket
by the spider which allows it to
move freely back and forth. When
electricity passes through the coil
a magnetic field is produced
which interacts with the magnetic
field of the magnetic which
causes the coil and cone to move
producing sound.
Christmas Lights
These small, low-voltage bulbs with normal house current are connect in series. If you
multiply 2.5 volts by 48, you get 120 volts, and originally, that's how many bulbs the
strands had. A typical strand today adds two more bulbs so that there are 50 lights in the
strand -- a nice round number. Adding the two extras dims the set imperceptibly, so it
doesn't matter. The lights in a 50-bulb strand are wired like this:
3
Christmas Lights
If you look closely at a bulb, you can see the shunt wire wrapped
around the two posts inside the bulb. The shunt wire contains a
coating that gives it fairly high resistance until the filament fails. At
that point, heat caused by current flowing through the shunt burns
off the coating and reduces the shunt's resistance. (A typical bulb
has a resistance of 7 to 8 ohms through the filament and 2 to 3
ohms through the shunt once the coating burns off.)
2
Christmas Lights
Although you can buy simple 50-bulb strands like the one shown, it is more
common to see 100- or 150-bulb strands. These strands are simply two or three
50-bulb stands in parallel, like the ones pictured. If you remove one of the bulbs,
its 50-bulb strand will go out, but the remaining strands will be unaffected. If you
look at a strand wired like this, you will see that there is a third wire running
along the strand, either from the plug or from the first bulb. This wire provides
the parallel connection down the line.
1
Making a Mini Flashlight
If you hook a mini-light bulb up to a normal AA battery, the bulb
will light just like a flashlight bulb. It will be dim, however,
because the bulb expects 2.5 volts rather than the 1.5 volts the
battery is generating. You can put two batteries together to
create 3 volts, or you can hook the bulb up to a 9-volt battery as
shown below:
Because you are driving the bulb at a significantly higher
voltage than it expects, it will burn extremely brightly and
will not last very long (perhaps 30 minutes or an hour).
0
Toaster
The basic idea behind any toaster is simple. A toaster uses infrared radiation
to heat a piece of bread. When you put your bread in and see the coils glow
red, the coils are producing infrared radiation. The radiation gently dries and
chars the surface of the bread. The most common way for a toaster to create
the infrared radiation is to use nichrome wire wrapped back and forth across
a mica sheet.
Nichrome wire is an alloy of nickel and
chromium. It has two features that make
it a good producer of heat:
Nichrome wire has a fairly high
electrical resistance compared to
something like copper wire, so even a
short length of it has enough resistance
to get quite hot.
The nichrome alloy does not oxidize
when heated. Iron wire would rust very
quickly at the temperatures seen in a
toaster.
nichrome wire
mica sheet
Light Bulb
The base, of a light bulb has two metal contacts,
which connect to an electrical circuit. The metal
contacts are attached to two stiff wires, which are
attached to a thin metal filament. The filament sits
in the middle of the bulb, held up by a glass mount.
The wires and the filament are housed in a glass
bulb, which is filled with an inert gas, such as
argon. When electric current flows from one
contact to the other, through the wires and the
filament the electrons zip through the filament and
bump into the atoms that make up the filament.
The energy of each impact vibrates an atom -- in
other words, the current heats the atoms up.
Electrons in the vibrating atoms may be boosted
temporarily to a higher energy level. When they
fall back to their normal levels, the electrons
release the extra energy in the form of photons or
light.
Hair Dryer
A hair dryer needs only two parts to dry your hair:
a simple motor-driven fan
a heating coil
Hair dryers use the motor-driven fan and the heating coil to transform electric
energy into convective heat. When you plug in the hair dryer and turn the switch to
"on," current flows through the hair dryer. The circuit first supplies power to the
bare, coiled wire of the heating element, which becomes hot. The current then
makes the small electric motor spin, which turns the fan. The airflow generated by
the fan is directed down the barrel of the hairdryer, over and through the heating
element. As the air flows over and through the heated coil, heat rising from the coil
warms the air by forced convection. The hot air streams out the end of the barrel.
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