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Electricity and Electrical Power
Miller Heights Elementary
School, Academic Year 2011-2012
Grade 5 |
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| Dr. DeLeo told us that a magnet produces something around it that we can't see. It is called a magnetic field. This is what makes it so hard to push magnets together when held a certain way. He then showed us how we could see the magnetic field by sprinkling steel needles on a piece of paper just above a magnet. |
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| Dr. DeLeo told us that electricity and magnetism are related to each other. As seen on the left, electricity from a battery produces magnetism; this is called an electromagnet. |
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Dr. DeLeo asked us if we knew what the word "symmetric" meant. Of course we knew! He told us that nature is often symmetric, and that not only can we use electricity to make magnetism, but we can also use magnetism to make electricity. Electricity and magnetism are related to each other. We discovered that we could make electricity by moving a magnet in and out of a coil of wire. |
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So, a moving magnet causes electricity to flow through the wire! This is a very important observation because it tells us how we can take the energy of something moving and turn into electricity (electrical energy)! We noticed that no electricity is produced when the magnet isn't moving.
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| Dr. DeLeo showed us how this principle is used to generate electricity in one of those flashlights that you shake back and forth. We could see a magnet going back and forth through a coil of wire, just like in Dr. DeLeo's coil demonstration. |
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In a generator, electricity is produced as a coil of wire is spun around right near a magnet. Dr. DeLeo brought hand crank generators.
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| We used one to give Dr. DeLeo a shock (only kidding). He also showed us how the electricity generated by the generator could be used to make another generator spin. A generator is simply an electric motor in reverse! |
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Electricity is a stream of electrons flowing through
the metal in a wire. In most electrical wires, the metal
is copper, and it is covered by an insulating plastic.
Electrons are a part of the atoms that make up the metal.
When the atoms come together to form a metal, the electrons
come loose and move freely. A battery, or a generator, creates a force
on the electrons that makes them move, and this is an
electrical current, or electricity.
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The picture on the left
below shows a real electrical wire, like the kind in the walls
of a house. The black part is the plastic insulation,
and the copper colored part, where the insulation was
removed, is the copper metal that carries the electrons
- the electricity. The drawing on the right shows how
the electrons come loose from the atoms that make up the
metal and flow through the wire. A battery creates a force
on the electrons that makes them move, and this is an
electrical current, or electricity.
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We learned how to make electrical
circuits. In our circuits, electricity flows from a battery into
a switch. And not just a toy switch, but a real switch
from a real hardware store, just like in our house!
From the switch, the wire went to a light bulb, and
then back to the battery. This is a complete circuit
- starting and ending at the battery. Dr. DeLeo made us sing "do..dodo..do.dodo..“ as we traced the path. We didn’t really know what the “do..do’s” were about, but it was funny. To see a VIDEO, click the play button on the picture on the right. The photos below show us carefully examining the wiring diagrams.
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Here are the wiring diagrams we followed. From left to right, we have a “simple” circuit, a “series” circuit, and a “parallel” circuit.
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Finally, we began to construct our circuits. We connected wires to other wires using “wire nuts.” First you place the bare ends of two wires next to each other. Then you place the wire nut over both of them, like a hat. Finally, you twist the wire nut to tighten it. Rightsy-tightsy, lefty-loosey. Not only does the wire nut keep the wires from coming apart, it also holds them so tightly together that electricity can flow from one to the other.
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| We used a screw driver to connect wires to the real switches, just like we were grown-ups. |
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| We got some help from our teachers. Three graduate students (shown on the left) from Lehigh University, where Dr. DeLeo works, helped one of our classes as well. |
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| But, mostly we were on our own. After all, we are almost in middle school! |
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And, it worked!! After we wired the simple circuit, we made more complicated circuits using two switches, the series and parallel circuits.
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Dr. DeLeo brought in a make believe wall so we could see what the wires look like in the walls of our house. The wires in the make-believe wall get their electricity from a battery, so it was safe to touch it. BUT!! .. Dr. DeLeo told us that we should never touch the wires in a real wall since that would be very, very dangerous! The wires in the walls of our house use high voltage. The make believe wall had a switch that turned on a light, and a button that made a door bell ring. We had fun making noise with the door bell. We got to ring the door bell every time we got one of our circuits to work. To see a VIDEO of us ringing the bell, click the play button on the picture on the left. Also see the photos below.
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Dr. DeLeo said that series and parallel circuits were like computers since they could make decisions. The series arrangement of switches is called an “AND” gate because the light only lights up if switch 1 AND switch 2 are on. Dr. DeLeo asked us to guess the name. When he said "Switch 1 AND Switch 2," he screamed out the word "AND" to give us a hint. The parallel arrangement of switches is called an “OR” gate because the light lights up if switch 1 OR switch 2 is on. This idea is the basis for computers, digital watches, video games, and many of the electrical devices we use every day.
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| After we put the circuit kits away, Dr. DeLeo gave us time to explore some stations he had set up around the classroom. We used electrical meters to measure voltages. |
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| We used a vertical windmill to generate electricity to power a light. |
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| We used solar cells to produce electricity. |
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| We used hand-crank generators to power lights... |
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| ... and to power electric trains. |
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Oh, and one last thing. We got to see something very surprising when those new types of (LED) Christmas lights are spun around. You can see from the pictures that the lights are actually blinking on and off!
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| This is because the electricity that comes out of outlets is "Alternating Current" (called "AC"), meaning it flows back and forth. And since electricity can flow through a diode (the "D" in "LED" - light emitting diode) only in one direction, the light is on half of the time and off the other half - on and off 60 times every second! |
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We were also given a magnetic field viewer that lets us see the magnetic field around a magnet. They are so cool!
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I hope you have enjoyed this web presentation as much as we enjoyed sharing the actual learning experience with your son or daughter. Although we have endeavored to exclude photographs where permission has been denied, it is possible for errors to occur. If you would like us to remove a photograph of your son or daughter for any reason, please send me an e-mail message at lgd0@lehigh.edu or call me at 610-758-3413, and we will remove it promptly. Please note that we will never associate a child's full or last name with a photograph except in circumstances where special permission was explicitly provided. Thank you. Gary DeLeo. |
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