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Electricity and Electrical Power
Asa Packer Elementary
School, Academic Year 2010-2011
Grade 5 |
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Dr. DeLeo started this program in a very strange way. He gave us a battery, a coil of wire and a nail, and then he told us to begin. "Begin what?" we asked. But, he didn't tell us. However, it didn't take us long to figure out what he had in mind. And, very quickly, we had constructed "electromagnets," and we were using them to pick up the nails!
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| Some students were asked to come to the front of the room and describe what they had discovered, like the two students in the picture just to the right. We could see that it is difficult to be a teacher! If you click the play button on the picture on the far right, you will see a VIDEO of us with our electromagnets. |
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We discovered that the magnet would pick up other things made of metal, like an electrical switch and one of our earrings. But, it didn't attract all metals. We discovered that magnets do not attract aluminum, as shown below on the right.
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Next, Dr. DeLeo showed us what happens when a (permanent) bar magnet is moved in and out of a coil of wire, which is in turn connected to a meter that measures electricity. 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. Dr. DeLeo pointed out that this effect is just the opposite of an electromagnet, where electricity is used to make magnetism.
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Ms. Richter, a graduate student from Lehigh University (where Dr. DeLeo works), 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 demonstration. In a generator, electricity is produced as a coil of wire is spun around right near a magnet. Dr. DeLeo brought hand crank generators. We used one to give Dr. DeLeo a shock (below on the left, but only kidding). Using a hair dryer, he demonstrated how wind power could be converted to electricity with a vertical windmill, coils of wire, and magnets.
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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.
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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. Ms. Richter and Mr. Sofka, another Lehigh graduate student, helped us with our circuits.
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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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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 electric can flow from one to the other. We used a screw driver to connect wires to the real switches, just like we were grown-ups.
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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. Here are some pictures of us with our circuits. |
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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 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. Click the play button on the picture on the left to see a VIDEO.
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After we completed our circuits, we got to use special meters to measure the amount of electricity in our circuits. Actually, we measured the voltage.
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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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At the end of the program, Dr. DeLeo gave each of us a naturally magnetic rock called magnetite. We love science!
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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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