The easiest way to create a powerful magnetic field is by creating a powerful electromagnet. Electromagnets are used for everything from powering tiny electronic switches (called relays) to lifting huge pieces of scrap metal. The density of the winding, the amount of current flowing through the magnet and the material the wire is wrapped around determine how strong the field is.
Select a piece of iron for the magnetic core. A 6 to 8 inch long piece of iron, such as a large nail or spike, will create a powerful magnetic field, but you can use smaller or bigger rods if you prefer.
Wrap the rod in magnetic wire (see Resources). Start at one end and wrap the wire all the way to the other end. Cut the wire, leaving several inches of loose wire hanging off either end. Wrap it as tightly as you can. The tighter the wire wrapping, the stronger the magnetic field.
Tape the magnet wire to the iron rod to hold it in place.
Strip the insulation off the last inch of each end of the magnetic wire by heating it with a lighter or match. Clean off any residue with a clean cloth.
Stick the exposed ends of magnetic wire under the coils of a lantern battery. This will cause current to flow through the magnet, creating a magnetic field.
For a stronger magnetic field, try connecting the magnet to a 12-volt power supply.
If you put too much power into the magnet, it can overheat or trip the circuit breaker.