Video segment. Assistance may be required. Before beginning this section, let’s take a moment and watch a video about magnetic forces.

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You can see magnetic forces in electromagnets and wind turbines. Close Pop Up

Source: Electromagnetism - Magnetic Force: The Four Fundamental Forces of Physics, scishow, YouTube

Charges that are in motion also create a magnetic field and can exert a magnetic force on each other. Current in a wire can be used to create an electromagnet, which can be turned on and off. Some materials can also be used as permanent magnets due to the structure of their atoms. Electrons in atoms are in constant motion in two ways: they are in orbits around the nucleus, and they have a property called spin. This motion produces a small magnetic field around every electron. In most atoms, the electrons exist in pairs that cancel each other's magnetic effects. Iron, nickel, cobalt, and a few rare earth metals have enough unpaired electrons that the entire atom has a magnetic field. If enough of these atoms align their fields, they create magnetic domains.

Magnetic domains are randomly organized in a non-magnetized material.

rectangle broken into pieces with arrows pointing in random directions

Source: Magnetic factors-domains misaligned, School for Champions

Magnetic domains are aligned in the same direction in a magnetized material.

rectangle broken into pieces with arrows pointing in the same direction

Source: Magnetic factors-domains aligned, School for Champions

Regardless of how they are created–by alignment of microscopic domains or by controlling a current–all magnets have two magnetic poles: a north pole and a south pole. Just like electric charges, opposite poles attract and like poles repel. Unlike charges, however, you can never have one pole by itself. If you take a magnet and break it in half, you wind up with two smaller magnets–both with a north pole and south pole.

Interactive exercise. Assistance may be required. Click on the following bar magnet to break it in to two pieces.

In the next section, you will look at examples of electric and magnetic forces in everyday life.