Overview: Our goal here is to make a simple electromagnet that can pick up objects made of iron or steel, without using a magnet.
Materials: a long metal bolt, a roll of insulated copper wire, three battery holders, and five alligator clips, a pair of scissors, 9 AA batteries, and small iron objects.
Step 1: Wrapping the wire.
1. Wrap the bolt with the copper wire by coiling around it with the loops as close as possible, the more loops you add, the greater the magnetic force generated by the circuit.
Step 2: Hooking up the circuit.
2. daisy chain the wrapped bolt and three battery packs using alligator clips, in a circuit as shown above.
Step 3: Using your magnet.
3. Try out your magnet by holding the wrapped bolt nearby iron objects, see if it picks up them, if it does, then congratulations, you've got a working magnet!
Step 4: TEST RESULTS
If successfully connected, as shown here, you can pick up many different iron objects as well as attracting and repelling other magnets as well. Just hold your magnet near the object, and it will either stick or be pushed away.
Step 5: Explanation.
The bolt becomes magnetic once a current is applied to the coil wrapped around it because electric currents produce magnetic fields. If the wire is wrapped around a coil, the magnetic fields will be concentrated in the loops, which is strengthened when its wrapped around a core, normally the atoms in iron or steel are pointing random directions, but when a current is applied to them, they line up pointing in one direction, and their magnetic fields will add up to create a larger magnetic field that attracts objects, eventually if you give it enough time, the bolt will become permanently magnetized and changing the electric current won't affect it anymore.