There is an invisible field that underlies the entire universe, like a net stretching in every direction.
While the field is intangible, it will often ripple with energy. Each ripple is called a photon, and their possible range in size is called the electromagnetic spectrum.
The field also gives electrons their charge, and this charge 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.
It comes from the electromagnetic force, one of the four fundamental interactions of the universe that determine the interactions of all matter.
The electromagnetic force is responsible for:
Forming atoms by attracting protons and electrons. If this part was 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 part was turned off, everything would turn into a puddle of weird goo.
The polarity of molecules like water, allowing it to dissolve lots of minerals which is the precursor to life. If this was turned off, the water in our blood and cells would expel every dissolved molecule and we’d instantly die.
Allowing electrons to flow across a surface, creating electricity. If this was turned off, modern civilisation would collapse.Making magnets work by combining the charge of electrons. If this was turned off, modern civilisation would collapse again.
Let’s quickly go through these roles.
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 magnets.
This relationship gives atoms their shape, and but also allows bonds between atoms to form through the sharing or exchange of electrons, and this is how atoms join together to form molecules.
Without this bond, all of chemistry, and thus all of life, is impossible. From this perspective, the electromagnetic force is quite literally the glue that holds our reality together.
Repelling electrons from other electrons
Even though everything is made up of atoms, and atoms are mostly empty space, it’s the repulsion of their electron clouds from each other that prevents you from sinking into your chair and down through the floor and into the center of the Earth.
The electrons on the surface of your clothes and body are repelling the electrons on the surface of your chair which are pushing back with equal force, like each one is lined with a thin layer of repelling magnets.
This repulsive charge 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 also 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.
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.
These electromagnets 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.
The electromagnetic force underlies much of our reality, and learning to manipulate it has been instrumental in creating the advanced technology of the modern world.