How to Create an Electromagnetic Field

Nail made into an electromagnet

Electromagnets are metals that can be easily magnetized (usually because of their iron or nickel content) by loops or spirals of a moving electric current surrounding them. When the current is shut off, the metal loses most of its magnetism. You will see electromagnets used in remote entry systems, so that you can unlock a door from a distance. If you wind an electric current around an empty space, it will create a magnetic field, and any metals you place within the field will become magnetized.

Things You'll Need

• Three pieces of insulated electrical wire Long coil of uninsulated copper wire (at least 80 feet long) Two size D batteries Metal paper clips (at least four) Tall drinking glass (glass better, plastic OK, paper bad) Resistor (optional) Metal spoon or screwdriver

Instructions

Power Source

1. Tape the two batteries together so that each has a different end facing up. Make sure they are very secure and do not roll, or else you may lose your electrical current.

2. Take two of the insulated wires and attach one to each of the paperclips. One should be attached on the end to each battery.

3. 

   Place one of the paperclips across the tops of the two batteries. If the paperclip does not reach to the center of each battery, you may have to unbend it so that it is longer.

4. Affix a strip of tape along the paperclip and halfway down each battery. Be sure to keep the paperclip in contact with the center of each battery and keep the free end of each wire accessible.

5. Turn the batteries over, and do the same to the other side. Again, make sure that this paperclip also makes contact with the center of the ends of the batteries both before and after affixing the tape.

Electromagnet

1. Leave about six inches of copper wire straight, and then start wrapping the rest of your copper wire around the middle of the glass, staying away from the mouth and bottom as you wind.

2. After at least 100 coils around the glass, make sure you have at least six inches of copper wire straight and free at this end of the coil as well.

3. Connect one of the wires from the power source to one of the free ends of your copper wire coil. Make sure the copper connects with the metal part of the insulated wire.

4. 

   Connect the other wire from the power source to your resistor. The third copper wire will go from the other terminal of the resistor to the other free wire of the copper coil.

5. Test the magnetic field inside the glass by taking metal objects and placing them inside the glass. They should become magnetized while the current is flowing through the copper coil. Paperclips will stick together. The metal part of a screwdriver or the spoon sticking out of the glass should be magnetized while the current is on, attracting other metal objects to it.

Tips & Warnings

• Iron is the most easily magnetized metal. Steel has iron in it, so it will work as well. When testing your magnetic field, do not pick aluminum or copper.

• Without the resistor, the copper coil and glass could get hot. Make sure there is nothing flammable beneath your copper-wound glass, and be careful not to burn your skin on it while the current is on or a few minutes after you disconnect the wires. Consider wrapping a rag or towel around the copper coil to handle it.

References

• How to Build Power Pack

Resources

• Read this Article in Spanish