One of the simplest science projects, that you can undertake, is building an electromagnet. When making one, you will get a practical understanding of how electricity and magnetism are the two sides of the same coin. The specialty of an electromagnet is that, unlike naturally occurring magnets, their magnetism can be switched on or off at will.
How to Create One?
Every atom, with a spinning electron around it, is a natural magnet. In some materials, the magnetic fields of most atoms are aligned in the same direction. This gives rise to an overall strong magnetic field.
Every small current gives rise to a magnetic field around it. The idea behind the creation of an electromagnet is based on this simple principle. Passing an electric current through a metal wire gives rise to a magnetic field around it. The strength of this magnetic field is directly proportional to the current passing through the conductor, such as a copper wire.
In order to create a denser magnetic field, the conductor is wound around a cylindrical iron core. The magnetic field, that is created around the conductor, induces magnetism in the iron core, around which it is wound, creating an even stronger magnetic field in the process.
The magnetic field created by an electromagnet, lasts only as long as the current is flowing within the conductor. So, the magnetism can be switched on or off at will. This switching property makes them useful in many devices.
If you have ever been to a junkyard, you must have noticed the giant electromagnet that is used to lift heavy metals off the ground and drop elsewhere. Many other gadgets like electrical relays work, using them. One striking example is the Maglev (magnetic levitation) trains.
The wheels of these trains are elevated because of the magnetic repulsion between the rails and wheels, which are both converted into electromagnets. Due to the decrease of friction between rails and wheels, these trains travel a lot more faster than normal ones, because the electromagnetic force overcomes gravity.
Making an Electromagnet
The things you will need are about 1 or 2 foot of copper wire (or telephone wires), a long iron nail, a wire stripper, glue/tape, and a DC battery. Kids are advised to take help of an adult, when making the electromagnet.
Strip the Wire
The first step is to strip the wire of all its sheathing, using a wire stripper. This is essential, as it will expose the metal conductor inside.
Wind it Around the Nail
Wind the stripped metal wire around the length of the nail. Make the windings as close as possible, to ensure that the magnetic field is denser. Cover more than three fourth of the nail and leave some length of unwound wire at both ends. You can apply glue on the nail before winding or apply tape at the ends to secure the winding. What you have now created is called a solenoid.
Connect Loose Ends with the Battery
The last part of the job is to connect the loose ends of the wire to the DC battery. You could tape the wire ends to the positive and negative terminals of the battery. With that, your electromagnet is ready. With the connection of the wire ends to the battery, the circuit will be completed and current will flow through the wire, creating your very own electromagnet. Test it, by bringing it near iron filings, which will immediately cling to it. Use a low power, 1.5 V battery, to be on the safer side.
Go ahead and build an electromagnet on your own. It will be your first lesson in electromagnetism. Remember that where there is a current, there is a magnetic field. All types of magnetic effects are caused by changing electric fields.