There is an invisible field that underlies the entire universe, like a net stretching in every direction.
While the field is intangible, but it will often ripple with energy (the ripples are called the electromagnetic spectrum) and give charge to certain particles (like electrons). This charge is the focus of this post, and it is responsible for almost all of the interactions and phenomenon that we see in everyday life.
The heat you get from rubbing your hands together, the solid sensation of a brick wall, and the resistance you feel from trying to force two magnets together are all different ways of perceiving the same thing.
They come from the electromagnetic force, one of the four fundamental interactions of the universe that determine the interactions of all matter.
It influences almost all of the everyday things that we see around us, including:
- Forming atoms by attracting protons and electrons. If this were to be turned off, the Earth, the sun, and everything else in the universe would instantly be turned into plasma.
- Making atoms resist each other by repelling electrons from other electrons. If this were turned off, everything would turn into a puddle of weird goo.
- Allowing electrons to flow across a surface, creating electricity.
- Making magnets work by combining the charge of electrons when they’re all spinning the same way.
- The polarity of molecules like water, allowing it to dissolve lots of minerals which is the precursor to life.
Let’s quickly go through these one by one.
Attracting protons and electrons
The electromagnetic force gives a positive charge to protons and negative charge to electrons, and they’re inherently drawn to each other like a ball is drawn to the bottom of a hill.
Repelling electrons from other electrons
The repulsive electric charge between electrons that it creates is why atoms that touch resist each other rather than simply merging together despite consisting mostly of empty space. This repulsive force becomes the root cause of all friction and pressure.
The concept of repulsion is responsible for electricity. At its most basic, electricity looks like this:
You have a sheet of metal. It’s made of atoms like in the picture below, with their outer layers being made of buzzing clouds of electrons.
A surface of metal atoms
If you were to force one extra electron into this surface, something interesting will happen. The electron will land on top of the nearest atom and settle in. But the repulsion between electrons will force a different electron out, which will become homeless. It will jump to a nearby atom and force another electron out and so on, until at the edge of the sheet an electron pops out. The ‘flow’ of these electrons, which happens very quickly, is electricity.
Rather than a sheet of metal, it makes more sense to make it into a long, thin wire, so that the electrons will move in a predictable direction. This repulsion of electrons for each other like pineapples and pizza is what turns all electric motors and powers all electronic devices.
Magnets are made by exposing certain kinds of metal to a powerful magnet when they’re being smelted (i.e. when they’re still liquid). The magnet will force the electrons in the metal to spin in the same direction, and when it solidifies you have a permanent magnet. Their negative charge becomes cumulative, and is felt beyond the physical shape of the magnet in a ‘magnetic field’.
Electromagnets work a bit differently. An electromagnet is made by tightly coiling a wire around a stick of iron, and passing electricity through the wire. The density of all the negatively charged electrons flowing past in a tight place also creates a magnetic field.
It can be used to push things around, and this is exactly what an electric motor does. This concept has been called “the greatest engineering achievement of the 20th Century”. You’ll be surrounded by electric motors right now, in fans, clocks, electric toothbrushes, washing machines, dryers, drills, hard drives, DVD players, vacuum cleaners, pumps, Tesla cars, and even the tiny motor that makes your phone vibrate.
Lightning is electricity travelling through air instead of a metal wire