14-billion-years-later: Electromagnetism...

Electromagnetism

Possibly one of the most important things in anyone’s life, but also one of the least acknowledged or understood. Electromagnetism is one of the 4 fundamental forces (the others being the strong and weak interactions and of course gravity) and it literally shapes the world around us. It’s the force that holds electrons around atoms and also what gives shape to the molecules and structures that we see in the world around us. In fact it’s what allows us to see the world around us as light is essentially just a changing magnetic and changing electric field at right angles. This is because a change in one of the fields creates the other and vice versa, so a growing or shrinking magnetic field will cause a fluctuating electric field, which will in turn create another magnetic field. This is what allows light waves to propagate through empty space; it is its own medium.

A changing magnetic/electric field is also the same principle used in electric motors and makes up the last two of Maxwell’s equations: Faraday’s Law of Induction (that a magnet in motion generates a current in a wire) and Ampere’s Law (that a charged particle in motion generates a magnetic field). The uses of electromagnetism are far more important than those of gravity yet it remains the awkward middle child of the force family. From transformers to our own forms, it is electromagnetism we have to thank.

The image shows how magnetism and electricity can be combined to make a motive force. Neat huh? Pretty easy to make at home too if you’re bored.