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GRADES 5 - 8
ELECTRICITY
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GRADES 5 - 8
ELECTRICITY
BACKGROUND INFORMATION:
Using electricity for power has become a
part of our everyday lives. Street and stoplights
help guide and light your way at night. Kitchen appliances
use electricity to preserve and cook your food.
Buildings use electricity to provide air
conditioning or light for your comfort and
supply power for computers and other
business machines. Electricity is used to
power your entertainment systems.
Although you may relate the electricity
your appliances, computers or televisions
use with an electrical outlet and a plug, the
outlet does not generate the electric power.
The outlet taps into an electric current from
power lines connected to a large generator
from your power company. That generator
(which may be miles and miles away) creates
the electric power. When you turn on a light
switch, you don't "create the electricity". Turning
on the light switch directs an existing electric current
into the appliance or machine you are using.
Another device that creates electricity is a
battery. The battery in your wristwatch or
flashlight generates an electric current to
power those devices.
Battery Connector And Battery
How is
electricity created? Electric power comes from
electrons -- tiny atomic particles all matter
contains. Under certain circumstances and
for certain substances, electrons can be
passed from one object to another.
Have you ever walked over a thick carpet
and gotten an electric shock? Have you ever
combed your hair on a dry, cold day and had
your hair stand up, or your comb pick up
small pieces of paper. These are all examples
of static electricity. There is a transfer of
electrons from one object to another (example,
from the carpet to your shoes).
The Comb's Electric Field Attracks Small Pieces Of Paper
Static electricity is produced differently
from the electricity you use in your appliances.
When you "plug" one of those appliances
into the wall socket you are plugging into an
electric current.
Just like water flows in a current, so does
electricity. When you walked across the carpet,
electrons were transferred, but there wasn't a flow
of electrons you tapped into to use.
Batteries and generators both produce electric
current. The ampere is the unit used to
describe the rate of electric current flow.
If you examine any battery you will see
that it has two terminals (end points). One
terminal is marked positive (+) and the other
terminal is marked negative (-). An electric
current is produced through the chemical
reaction of the materials inside the battery
and flows through the negative terminal to
the positive terminal. The volt is the unit
used to describe the amount of current a
battery produces.
In this activity you build an electrical circuit.
What is a circuit?
An electric circuit is the pipeline
or pathway for the electric current.
In this activity:
Buzzer Circuit Diagram
A resistor is used in this activity.
Its purpose is to modify the intensity of the current.
The resistor is made out of a material which
"resists" the current going through it. It is
used in an electric circuit to regulate or
or control the electric current. What happens as
you increase the resistance?
The resistor changes the brightness of the light bulb and loudness of the
buzzer.
Resistors
are calibrated in ohms. The different colored bands on the
resistor signify the number of ohms.
Resistors
Click On The Picture To See The Movie
The electric current flows through
each of these parts.
REFERENCES:
Freeman, Ira M. and Durden, William J., Physics Made Simple,
Doubleday, New York, 1990.
Macaulay, David, The Way Things Work, Houghton Mifflin Company, Boston, 1988.