Resources Needed:
| 1 lemon or lime |
1 iron screw 5 cm long |
1 brass screw 5 cm long |
| 1.5 volt light bulb |
3 insulated wires with striped ends approx. 15 cm |
D cell battery |
| 1 D cell battery holder |
1 light bulb holder |
comb |
| penny |
rock |
metal spoon |
| fabric |
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Your
Task: Complete 4 of the 6 activities listed below in red. Enjoy!
BATTERIES
Batteries
are assembled from cells, connected in series, to increase the voltage
available.
In a cell,
chemical energy is converted into electrical energy.
Cells
may be either PRIMARY or SECONDARY types.
A primary
cell is discarded when its chemical energy is exhausted.
A secondary
cell can be recharged.
The most
common primary cell is the zinc/carbon (Leclanche) as used in torches,
portable radios etc.
1. Building
your own battery. Demonstrate your battery to the class. Click
here for directions.
WHAT IS ELECTRIC CURRENT?
An electric current
is a flow of microscopic particles called ELECTRONS flowing through wires
and electronic
components.
It can be likened
to the flow of water through pipes and radiators, etc.
As water is
pushed through pipes by a pump, electric current is pushed through wires
by a
battery.
Hot water does
work by heating radiators.
Electric current
does work by heating fires, lighting lamps, ringing bells, electroplating,
etc.
A basic law
of the universe is that like charges repel and unlike attract. Two negatives
will repel
each other.
A negative and a positive will attract each other.
An electron
has a negative charge.
The negative
(-ve) terminal of a battery will push negative electrons along a wire.
The positive
(+ve) terminal of a battery will attract negative electrons along a wire.
Electric current
will therefore flow from the -ve terminal of a battery, through the lamp,
to the
positive terminal.

2. Using two or three wires,
one battery, and one light bulb, build a simple circuit, a parallel
circuit,
and a series circuit.
Click
here for diagrams.
For
more basic electronics diagrams and explanations
VOCABULARY
-
circuit a closed loop of conductors through which charges can flow
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conductor a substance through which electrical charges can easily
flow
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current a flow of electrical charges
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generator a device for producing electrical current by moving a
coil of wire in a magnetic field
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insulator a material through which electric charges cannot move
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ion an atom that has gained or lost one or more electrons and is
thus a charged particle
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switch a device that closes or opens a circuit, thereby allowing
or preventing current flow
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voltage the pressure behind the flow of electrons in a circuit
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3. Create a word search or
crossword puzzle using the vocabulary words above.
Print
your word search and crossword puzzle.
Test other
students by printing the answer keys.
Click
here to create the word search or a crooss word puzzle
4. Visit Frankenstein's Lightning
Lab. on electrical safety. Place the cursor on a part ot the house
to learn
a safety rule.
Make a
poster which illustrates one of the safety rules. Click
here to go to Frankenstein's Lab
CONDUCTORS
These are
materials in which it is easy to get electrons to move and provide a flow
of electric current.
Conductors
are mostly metals such as gold, silver, copper, iron and lead.
Carbon
is a conductor as well as some gases (as in fluorescent tubes) and water
containing some
chemicals.
These
are not perfect conductors and offer some resistance to the flow of current.
The resistance
of a conductor (such as a metal rod) is determined by three things:
(1) its
length. The longer its length the higher its resistance.
(2) its
cross-sectional area. The bigger this is the lower is its resistance.
(3) the
material of which it is made.
All materials
have RESISTIVITY.
The higher
the value of resistivity the higher the resistance.
It is
measured in OHM METERS.
length x resistivity
Resistance = -------------------------------
cross-sectional area
5. Find out which objects
conduct electricity. Build the tester described in the conductivity
experiment.
Fill in the chart.
Conductivity
experiment
| Name of object |
Conducts electricity |
Doesn't conduct electricity |
| comb |
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| fabric |
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| metal spoon |
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| penny |
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| rock |
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6. The measure of energy
per unit charge is measured is called voltage (V) and the unit of
measurement is called volts.
Resistance
inhibits the amount of current running along the circuit.
Use the
voltage
simulator to light the light bulb.
Record
your results. Voltage
Circuit Simulator
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Quick Links - Select and click
"Go"
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