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Electricity and Electrical Power
Miller Heights Elementary
School, Academic Year 2010-2011
Grade 5 |
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Dr. DeLeo told us that electricity and magnetism are related to each other. As seen on the left and below on the left, we can use electricity from a battery to produce magnetism; this is called an electromagnet. Notice in the center photo below how the nail falls when the wires are removed from the battery. Magnetism is also produced by a permanent (bar) magnet. 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. Dr. DeLeo showed us how we could see the magnetic field by sprinkling steel needles on a piece of paper just above a magnet (photo below on the right). |
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Many things in nature are symmetric, and just like we can use electricity to produce magnetism, we can use magnetism to produce electricity. The left and middle pictures below show how we can make electricity by moving a magnet in a coil of wire. The right picture below shows how this principle is used 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.
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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 that we could use to make electricity. We could even use one generator to make another one spin, as seen in the photos. |
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Using a hair dryer, he demonstrated how wind power could be converted to electricity with a vertical windmill, coils of wire, and magnets. You can see a VIDEO by clicking the play button on the right photo below.
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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. Here we are carefully
examining the wiring diagrams as we begin to build our circuits. 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. Mr. Snyder was a little concerned at first about us using screw drivers. But we did very well, with a little help from our teachers. |
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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. Notice the nice sweatshirt!
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| Below and to the right are photos of us ringing the door bell. |
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| Dr. DeLeo asked us what we discovered from the series and parallel circuits. We helped him get the data from our classmates and write the results on the board, as shown in the VIDEO on the far left. Just click the play button on the picture. |
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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. 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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Dr. DeLeo also gave us a chance to turn the cranks on hand-held generators to make electricity. We used the electricity to light up little light bulbs and turn electric motors. We even used the electricity to make a toy train run on tracks. We also generated electricity using the energy from light, by using solar cells.
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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. You can even see the magnetic field of a magnet through your sweater! 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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