Simple Electromagnet

(Basic Electromagnetism Experiments and Project)

Introduction:
 An electromagnet is a device that becomes magnet when connected to electricity. Unlike permanent magnets, you can easily turn on or off the magnetic force in an electromagnet. The simplest form of an electromagnet is a metal rod (such as an iron nail) that you wrap some insulated wire on that. Electromagnets are used to make electrical bells, speakers, microphones, electrical valves, electrical door openers, electric motors, buzzers, vibrators, magnetic cranes, televisions, magnetic storage device, tape recorders and many more.

Continue to read and learn how you can make an electromagnet and what factors affect the strength of an electromagnet. Your electromagnet will have a core of iron nail and a coil of magnet wire.

Experiment 1: Make a simple electromagnet
 In this experiment you will make a simple electromagnet and then use a compass to identify the north and south poles of your electromagnet. Materials: Materials for this experiment include: Large Iron nail (such as 10d 3") 30 feet magnet wire 28 AWG Double C Battery holder Metal strip (used as key) 3 screws Piece of wood to install the the key

Procedure:

 Wrap one or two layers of masking tape on the nail to protect the wires from direct contact with nail. This nail will be the core of your electromagnet. Leave one foot of the magnet wire and then start to wrap the wire over the masking tape on the nail. This will be the coil of your electromagnet. Continue wrapping the wire until about one foot wire remains unwrapped. You may optionally twist the two remaining wires from near the nail to prevent the coil from getting unwind. (Count the number of turns of wire when winding. Record the number of turns of wire.) Use a piece of sand paper to scrub away the insulation from about 1 inch of the wire ends. You will notice a color change where the insulation is removed.
1. Mark 3 contact points on a wooden board and label them A, B and C. These points are 3.5 cm (1.5 inches) apart from each other. You will later insert one screw in each of the marked point.
2. Connect one wire of the coil to the red wire of the battery holder. (You can twist the wire ends to each other and then secure it by wrapping a tape over that. Another way to secure this connection is placing it under the cap of a screw you insert in a wooden board. That connection is marked as C in the above diagram.)
3. Connect the other wire of the coil to a screw B you insert on a board. This screw is also the contact for your key/ switch.
4. Pass a screw through the hole of small metal strip and then insert it in the position A in a way that the other end of metal strip stays over the screw B, but not touching it.
5. Connect the black wire of the battery holder to the screw A.
6. Insert the batteries in the battery holder. Your electromagnet is ready now.

Note: The diagram above shows the electromagnet nail is very close to the key and battery. Since you leave one foot wire from each end of the coil wire, your actual electromagnet will be about one foot away from the key and the battery holder. This distance is especially important for other experiments you will perform with your electromagnet.

Place a compass near the electromagnet and push the button over the screw B. Does the compass needle move? If it does not, there is a problem. Check all the contacts and try again. If it moves, you can continue with other experiments.

Experiment 2: Identify the poles of an electromagnet

Introduction: Identifying the poles of an electromagnet is important because the poles have opposite forces.

Procedure:

Place the electromagnet near the compass in a way that the tip if the nail is toward the compass. Push the button so the nail will become magnetized. The compass needle will move. If the north seeking end of the compass is facing the nail, then mark the tip of the nail with the letter N as north.  If the south seeking end of the compass is facing the nail, then mark the tip of the nail with the letter S as south.

The other end of the nail (the cap) must be the opposite pole; however, you must verify this. Turn your electromagnet 180 degrees so the cap of the nail will face the compass. Press the key again to magnetize the nail. If the north seeking end of the compass is facing the nail, then mark the cap of the nail with the letter N as north.  If the south seeking end of the compass is facing the nail, then mark the cap of the nail with the letter S as south.

Marking may be done by small stickers, by paint or by color papers. Usually color red is for north and color blue is for south; however, this is not a standard.

Experiment 3: Does the direction of winding coil affect the position of the poles?

Procedure:

1. ...............

Experiment 4: Does the direction of electricity affect the position of the poles?