Eli5: How do compasses work and what are magnetic fields?
In: Physics
If you know what magnetism is skip the first part.
First the basic of all this is magnetism. Magnetism itself is a quantum-mechanical effect and very complicated. It belongs to one of the “four fundamental interactions” of physics.
It basically constitutes of negatively charged parts and positively charged parts, which attract each other. This effect can be realized through electricity, where electrons charge something negatively and the “lack” of electrons charges positive. That’s called electromagnetism.
Every magnet projects his attractionits out of its own body to it’s surroundings, like gravity. The further away you are from the body the weaker the attraction gets though. That is the magnetic field. You can’t see magnetic force, but when we lay down metal shavings they align themselves along the magetic field making it visible.
The earth itself has an iron core that acts like a gigantic magnet, projecting it’s magnetic force as far out as space. So the whole earth is covered in a weak, but constant magnetic field. Like any magnet earth has a positive side and a negative side, attracting the opposite. A compass uses that by charging on side positive, which then points towards the negative side of earthand the other side negative, which then points to the positive side of earth.
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