LEVEL II: ELECTROMAGNET PROJECTS
PROJECT # 1
To construct a device ( an electromagnet) that will create magnetic force using electricity.
PART 1: Magnetism from electricity
Two ways to show that when electrons move through a wire they produce a magnetic field that will cause the wire to be repelled or attract to another magnetic field
Before you start take the magnet wire and cut about 1 foot of wire, then you will have to remove the insulation from both ends of the wire. Now, take a screw and connect it in hole1, when the screw is half way in the wood take one end of the magnet wire and wrap it around the screw and then screw tight. Take your small sheel metal piece (when you attach it to the wood it will be called your key switch) and put a screw inside the hole and then connect it in hole 2. Take your battery holder and keep in mind that the battery holder has two wires, one red and one black. The red wire is the positive side of the battery and the black wire is the negative side of the battery. So, now that you know take the positive wire of the battery holder and connect it in hole 2 with the key switch, now screw tight. Take another screw and connect it in hole 4 before you screw tight, take the negative side of the battery holder and the other end of the magnet wire and connect them with the screw, now you can screw tigh. When you finish this move your wood to the edge of a table, so that the wire is hanging from the table. Under the magnet wire place a chair with your group of 6 disc magnets, in a way that the magnets are close to the wire but not touching (pic). If the wire is moving wait a few seconds untill the wire stop moving, then push down your key switch. What did it happen?Lets try to get the same results with something different. Remove the chair and the magnets. Take a compass and put it on top of your wood. Take your wire and place it on top of the compass, now press the key switch and observe the compass at the same time. What happen?
What Is Happening:The way a battery works is by a source of electrical pressure that pushes electrons electrons through a wire. Then the electrons move from the negative end of the battery to the positive side of the battery. When these electrons move they produce a magnetic field that is in the form of a loop around them (pic). The direction of the arrows shown in the magnetic loop (figure B) is also the direction that a compass will point, if placed either directly above or below the wire. One method to determine the direction of the magnet loop os to use the "left hand rule." Using your left hand point your thumb in the direction that the electrons are moving, your fingers will wrap around the wire showing the direction of the magnetic field and also the direction that a compass will point.PART 2: Construction of the ElectromagnetOne consideration in building electromagnets is how many turns of wire to wind. In order to see what kind of effect does the number of turns has on the magnetic field produced, you will first construct two coils, one coil with 10 turns an another with 100 turns. Take your magnet wire and cut two pieces, one about 6ft of length and the other about 8ft. You will need to remove the insulations of both ends of each magnet wire.Take the piece of plastic straw included in your kit and cut it about 2 1\2'' and place the straw over the a nail. Take your magnet wire and begin about 2 feet from the end of the wire to wrap it around the top of the plastic straw about 1\4 from the end of the straw 10 turns. When you finish you can tape on each side so the wire won't remove from the plastic straw. Do the same thing with another piece of plastic and nail, but this time make it with 100 turns. Take your wood and remove all wires but keep the nails and the key switch in the same place. Take your battery holder and connect the negative side to the screw on hole 1. Take the positive side of the battery and connect it to one end of your electromagnet. The other end of the electromagnet connect it to the key switch in hole 2. Place a compass on the wood with the north arrow in the direction relative to the coil. Bring your electromagnet close to the west side of the compass, so when you press your key switch you will notice a small movement with the arrow moving away from the coil. Mark this location because you will repeat this with different electromagnets. Try this again but now with the 100 turn electromagnet. Only disconnect the electromagnet with the 10 turns and replace it with the 100 turn. Do the same process you did with the previous one. Make note and compare it with the first.
You now know that increasing the number of windings is increasing the strenght of the field. Take a nail cover it with a 2 1\2'' of plastic straw. Cut another piece of magnet wire but remember that it has to be more than 8ft because you will make 300 turns and also remember that you have to remove the insulations from both ends. Begin from 2ft of the wire and wrap it 1\4 from the end of the plastic. Wind 300 turns as close as possible making three layers. Begin turning from the top of the nail going your way down. When you get down stop at the end of the straw and make another layer going up again. When you get to top of the nail make another layer going down again. When you finish take the two ends of the wire and connect them together so they won't remove from the straw. Keep in mind that this strong electromagnet is the one you are going to make your telegraph. Now, remove the nail from the straw and connect it to your wood like you did with the others. Press the key switch and make note of what happen. Take the nail and inserted in the plastic straw. Press the key switch and make note of it.
This process helps us understand that different numbers of windings and different materials for the core have a different effect on the strenght of an electromagnet. Now, you will try an electrical pressure, but in order to do this you will need to use your strong electromagnet and remove any core material you mignt have in it to eliminate its effect. Now remove one battery from your battery holder. Tape one end of the electromagnet to the negative side of the battery, slowly bring close the electromagnet to a compass and touching periodically the other end of the electromagnet to the positive side of the battery. When you have reach a location on the east or west side of the compass make a spot with a piece of tape or your table were there has been movement. Put the battery back in the battery holder and do the same thing but with the entire battery holder. How much stronger is the magnet field? The way you can tell how many times stronger the field is, is by looking carefully at the amount of movement of the compass.
Try this last experiment for project 1. What do you think it would happen to the magnetic field of you put ohter items that use electricity into the same circuit as the electromagnet? Lets try it, take your wood, strong electromagnet, and battery holder. The negative side of the battery connect it two the screw in hole 1 and the other side of the batteryconnect it with one end of the electromagnet. Take the light bulb (the christmas light bulb) and connect its two ends in holes 3 and 4. The other end of the electromagnet connect it to the in hole 4. Take your hookup wire (the yellow wire) and cut about 7 1\2'' and remove the insulations from both ends. One end connect it in hole 3 and the other end connect it to the key switch in hole 2. Press the key switch. What happen?