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• A magnetic field is what electric fields turn into when an electrically charged object starts moving
• Magnets, in order to be magnetic, must have

  • Half filled outer shell of electrons so their intrinsic magnetic fields can align and not cancel out. All within...
  • Magnetic atoms which must be aligned
  • Magnetic domains which must all be aligned
• Navigation by magnetic compass
• The poles point north and south when suspended
• A compass is a bar magnet that always points north
• Like poles repel, opposite poles attract
• Opposite charges can be isolated
• Opposite poles are always found together
• Magnetism arises due to electron configurations
• Many substances have their electrons paired up with one spin up and one spin down in orbitals. So spins cancel out. However, some substances (iron, cobalt, nickel) have unpaired electrons. This can lead to ferromagnetism
• In ferromagnetism, the spins will align
• Magnetic domain which will generate a magnetic field
• The geographic poles mark earth's axis of rotation
• Magnetic poles arise due to the distribution of iron in earth's core
• The magnetic poles change their position slowly over time
• High energy charged particles race towards earth from the sun
• The magnetic field deflects these particles towards the poles
• Collisions with atmospheric particles produce aurora borealis
• The direction of the force from a magnetic field on a current running through a wire will be perpendicular to both the magnetic field and the current
• Currents are made up of moving electric charges, so it makes sense that a magnetic field would also exert a force on single electric charges that pass through it
• Special relativity is the fact that in our universe, length and time are not absolute
• Wire with current in it deflects nearby magnets
• To make an electromagnet, all you need is current through a wire. Seriously, that's it. It will be a terribly weak magnet though. To ramp up magnetic field lines from wires, we tend to wrap them in coils. These coils will result in a bunch of magnetic fields that agree with each other, resulting in a stronger total magnetic field. Stronger electromagnets are made out of tons of weak electromagnets, in a similar way as permanent magnets.