electrons move through
the atoms of a wire
Electrical
Circuits
What are generators?
How do they work?
Generators give us
electricity. They start with fuel.
They turn the fuel into electricity.
That makes light bulbs glow. It
makes TVs show the news. Let’s take a
look at how it works.
Electricity does not move like we do. It only moves through
conductors (KON-duck-tors). Conductors are used for wires. They have loose
electrons. The electrons move back and forth through the wire. Copper wire is a good
choice. Aluminum is, too. Even gold and silver work.
Electricity also needs a push to make it go. That is what a generator is for.
Generators use magnets. They move the magnets along a wire. The magnets push
the electrons inside the wire. They do not have to touch them. This makes a flow of
electrons. That is called electricity.
Think of a pipe. It is filled with Ping-Pong balls. What would happen if you pushed
one more ball into the end? All the balls would move along the pipe and bump the last
one out. This is like electrons moving along the wire.
+
–
Wires
Battery
(source)
Light
(load)
85
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#50161—Leveled Texts for Science: Physical Science
Amps and Volts
The generator’s magnet pushes. The electrons go down the wire. We can measure
this two ways. The magnet pushes a number of electrons. That is measured in amperes
(AM-peers). It is called amps for short. The magnet also puts a force on the electrons.
This is measured in volts.
Amps and volts are put together to see how much power is used. This is called watts.
Watts are amps times volts. That tells you two things. It tells you how many electrons
are moving. It also tells you how much force is behind them.
AC vs. DC
Thomas Edison made the first light bulb. He wanted to sell electricity. He wanted
to bring it into homes. He made a promise to light up New York. There was one
problem. The electricity for homes was direct current. That is called DC for short.
The electrons always went the same way down the wire. DC cannot go very far. The
electrons fall out of the wire. DC is not good for homes.
Nikola Tesla worked for Edison. He had an idea. He wanted to move the electrons
a new way. He made electrons go back and forth very fast. They changed direction
many times in one second. He called it alternating current. It is called AC for short.
This let electricity go much farther.
The two men both wanted their way. Edison wanted DC. Tesla wanted AC. In the
end, Tesla’s ideas worked best. Today, we use AC in our homes.
Electrons travel along this
wire to the bulb.
generator
Comprehension Question
How is electricity like balls in a pipe?
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© Shell Education
electrons move through
the atoms of a wire
Electrical
Circuits
What is a generator?
How does it work?
Generators give us
electricity. They start with fuel
from other things. This is turned
into electricity. Electricity is what
makes a light bulb glow. It makes a
television show the news. Let’s take a look at
how it works.
First, electricity does not move like we do. It only moves through conductors
(KON-duck-tors). Conductors are used for wires. They have loose electrons. The
electrons move back and forth through the wire. Copper wire is a good choice.
Aluminum is, too. Even gold and silver can be used.
Electricity also needs a push to make it go. That is what a generator is for.
Generators use magnets. They move the magnets along a wire. The magnets push
the electrons inside the wire. They do not have to touch them. This creates a flow of
electrons. That is electricity.
Imagine a pipe. It is filled with Ping-Pong balls. What would happen if you pushed
one more ball into the end? All the balls would move along the pipe and bump the last
one out. This is like electrons moving along the wire.
+
–
Wires
Battery
(source)
Light
(load)
87
© Shell Education
#50161—Leveled Texts for Science: Physical Science
Amps and Volts
The generator’s magnet pushes. The electrons go down the wire. We can measure
this two ways. The magnet pushes a number of electrons. That is measured in
amperes (AM-peers). It is called amps for short. The magnet also puts pressure on the
electrons. This is measured in volts.
Amps and volts are put together to see how much power is used. This is measured in
watts. Watts are amps times volts. Watts tell you how many electrons are moving and
how much force is behind them.
AC vs. DC
Thomas Edison invented the light bulb. He wanted to sell electricity. He wanted
to bring it into people’s homes. He also made a promise. He said he would light up
New York. There was a problem, though. The electricity for homes was direct current.
That is called DC for short. The electrons always went in the same way down the wire.
DC cannot travel long distances. The electrons fall out of the wire. DC is not good for
homes.
Nikola Tesla worked for Thomas Edison. He had an idea. He wanted to use
another kind of current. Alternating current makes electrons go back and forth very
fast. They change direction many times in one second. Alternating current is called
AC for short. This makes it easy for electricity to travel over long distances.
The two men both thought they had the best idea. Edison wanted DC. Tesla
wanted AC. In the end, Tesla’s ideas worked best. Today, we use AC in our homes.
Electrons travel along this
wire to the bulb.
Comprehension Question
generator
Describe an electrical current.
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#50161—Leveled Texts for Science: Physical Science
© Shell Education
electrons move through
the atoms of a wire
Electrical
Circuits
What is a generator?
How does it work?
Generators give us electrical
energy. It starts with energy
from other things. It turns that
into electricity. This energy is what
makes a light bulb glow. It makes a
television show the news. Let’s take a look at
how it works.
First, electricity moves through conductors (KON-duck-tors). Conductors
are materials that share electrons easily. The electrons move between the atoms. Copper
wire is a good choice. Aluminum, gold, and silver are other metals that can also be used.
Electricity also needs a push to get it moving. That is what a generator is for.
Generators move the magnets along a wire. The magnets push the electrons inside
the wire. They do not have to touch them. This creates a flow of electrons. That is
electricity.
Imagine a pipe. This is like the wire. It is filled with Ping-Pong balls. What would
happen if you pushed one more ball into the end? All the balls would move along the
pipe and bump the last one out. This is like electrons moving along the wire.
+
–
Wires
Battery
(source)
Light
(load)
89
© Shell Education
#50161—Leveled Texts for Science: Physical Science
Amps and Volts
The generator’s magnet pushes the electrons down the wire. Two things happen.
The magnet pushes a certain number of electrons along the wire. This is measured
in amperes (AM-peers). They are also called amps for short. The magnet also puts
pressure on the electrons. This is measured in volts.
Amps and volts are put together to see how much power is being used. This is
measured in watts. Watts are found by multiplying the amps and volts together. That
tells you how many electrons are moving and how much force is behind all those
electrons.
AC vs. DC
Thomas Edison invented the light bulb in 1879. He wanted to sell electricity. He
wanted to bring it into people’s homes. He promised to light up New York. There
was a problem, though. The electricity for homes was direct current, or DC for short.
The electrons always went in the same direction down the wire. DC cannot travel long
distances. The electrons fall out of the wire. DC is not good for homes.
Nikola Tesla worked for Thomas Edison. He had an idea. He wanted to use
another kind of current. Alternating current, or AC, makes electrons go back and
forth very fast. They change direction many times in one second. This makes it easy
for electricity to travel over long distances.
The two men argued. Edison wanted DC. Tesla wanted AC. In the end, Tesla’s
ideas worked best. Today, we use AC in our homes.
Electrons travel along this
wire to the bulb.
Comprehension Question
generator
How are AC and DC different?
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© Shell Education
Electrical
Circuits
electrons move through
the atoms of a wire
What exactly is a
generator, and how does
it work? An electrical
generator converts energy
from other sources into electrical
energy. This energy is what makes a
light or a television work when switched
on. To better understand how these forces
work, let’s take a look at how an electrical current and
electromagnetism are made.
First, electricity needs a conductor to move it from one point to another. Materials
that are good conductors have electrons that move easily. Copper wire is a good
conductor. Aluminum, gold, and silver are other metals that are sometimes used as
conductors.
Electricity also needs something to get it moving through the conductor. Generators
are often used to do this.
Generators use magnets to push the electricity along a wire. The magnets push the
electrons inside the wire without having to touch them. This creates a steady flow of
electricity.
Imagine a pipe. This represents the wire. It is filled with Ping-Pong balls. What
would happen if you pushed one more ball into the end? All the balls would move along
the pipe and bump the last one out. This is like electrons moving along the wire and into
an electrical appliance.
+
–
Wires
Battery
(source)
Light
(load)
91
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#50161—Leveled Texts for Science: Physical Science
Amps and Volts
As a generator’s magnet pushes the electricity along the wire, two things happen.
The magnet pushes a specific number of electrons along the wire. This electrical
current is measured in amperes (AM-peers), or amps. The magnet is also putting
pressure on the electrons. This pressure is measured in volts.
Amps and volts are put together to determine how much power is being used. This
is measured in watts. Watts are found by multiplying the amps and volts together.
That tells you how many electrons are moving and how much force is behind all those
electrons.
AC vs DC
After Thomas Edison invented the light bulb in 1879, he worked to bring electricity
into people’s homes. He also made a promise. He wanted to light up the city of New
York. There was a problem, though. The electricity for homes was direct current, or
DC. This is a current pushed through a circuit and flowing continuously in the same
direction. Low-voltage DC currents cannot travel long distances because there are such
high losses in the cables that carry them. That means DC is not good for powering our
homes.
Nikola Tesla, who worked for Thomas Edison, had an idea. He wanted to use
another kind of electric current. Alternating current, or AC, changes direction back
and forth many times in one second. This makes it easy for electricity to travel over
long distances.
The two men didn’t agree. In the end, Tesla’s ideas worked best. Today, the
electricity that comes from a power plant and is used in our homes is AC.
Electrons travel along this
wire to the bulb.
Comprehension Question
Compare and contrast alternating and
direct currents.
generator
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© Shell Education