Where does Magnetic Fields come from?

Our fifth activity was about sources of magnetic fields. Before I thought that these only come from those magnetic metals I used to play with and stick on the refrigerator's door. Until when we had a little experiment in Grade 6 where we wound an iron nail with copper wire and connected it to a battery. "Magically" it attracted all those small pins we had. I was twelve then, and I had no idea why they were like that. My teacher just told me that they were caused by electromagnetic forces.

Now that I'm in college, it was only then I learned that a simple current-carrying wire can create magnetic field. Through this experiment, I was able to understand the magnetic field, and its relationship with electric field.

First off, we observed the behavior of magnetic fields in natural magnets We measured the magnetic field strength of a magnet using a sensor. We found out that it is stronger on the poles than away from it. We saw something like the picture above, by putting a sheet of paper over it and sprinkling iron dust over it. Bits of iron aligned with the magnetic field lines. 

Next, we dis Oersted's experiment, wherein we connected a wire to the power source and placed a compass over it. When the switch was closed, the compass needle deflected because the current-carrying wire created a magnetic field. This phenomenon is described by Biot-Savart's Law wherein moving charged particles create magnetic field. In this case, the chraged particles moved in the conductor.

We then observed the magnetic field created by a solenoid: a coil made of varnished copper wire. We made a current run through it, making it an electromagnet. We observed the effect of the number of turns of coil with respect to the magnetic field. We noticed that the values dropped when we lessen the number of coils. This observation verifies the equation derived for solenoids, which is:

There was also an effect when different metals are inserted into the core of the solenoid

It was fun to know that magnetism doesn't only exist in permanent magnets, but also in simple wires that has current on it.