One of the easiest things to understand in chemistry is the model of an atom. An atom is like a mini solar system. It has a nucleus, which is like the sun, and electrons whirling around the nucleus, like planets.
After this it gets complicated fast, and since I am not a physicist or a chemical engineer, I can’t explain it with any authority. In fact it would be easier for all concerned if you didn’t literally believe anything you read here. But it turns out the nucleus is made of two kinds of particle, protons and neutrons. The protons and electrons have electrical charges that offset each other and make an energy balance in the atom. Each atom has a “weight” according to its number of protons, neutrons and electrons. In the subatomic world where the electrons, protons and neutrons live, there are many other particles — fermions and bosons being the main categories, with leptons, hadrons, photons and more and more defined all the time. There are also such things as antiparticles, where, for example, for every electron there is a positron, meaning an electron particle with an opposite electric charge. But the complications of particle physics here start to outdistance the recognizable natural world where this writing is trying to live.
There are structures underlying structures in the subatomic world. For example, inside atoms are different kinds of quarks, which the physicists call up, down and strange. There might be a particle called a graviton, which could carry the force of gravity, though no one yet knows for sure. There are electrically neutral neutrinos which effectively have no measurable mass and pass through material objects like lead and stars unhindered.
Odd names for odd objects.
Except, weirdly, they are not objects at all. For the sake of convenience, they are spoken of as objects and can be described mathematically as if they are objects. But in fact, it turns out the solar system model of the atom is itself fictional. Little objects called electrons do not revolve around little objects called neutrons and protons: There are no such objects. There are only behaviors of energy.
Neils Bohr, who was the primary creator of the solar system model of the atom in the 1920s, carefully warned everyone that the model is just a way of visualizing certain behaviors. In fact, Bohr warned that no language exists that can directly describe what is going on down there in subatomia. Atoms and particles are not things at all, in the way we understand “things.” They are behaviors.
These behaviors are known to exist, though, by two pretty definite sources of evidence. One source is mathematics. Mathematical equations that accurately describe activities in the world where objects do exist (which is where we live) lead directly to equations that describe behaviors of energy inside molecules, or in other words atoms (where we do not appear to live, it’s too small). The equations describe, not things as they are, but relationships between behaviors of energy. In subatomia, there is no there there. The location and velocity together of any given particle are never certain. Bohr’s solar system model of the atom is a way of visualizing how one kind of unlocatable behavior (electrons) relates to another kind of unlocatable behavior (protons and neutrons). And so on down the line.
The other source of evidence is streaks of light on film and computer screens. The physicists verify the predictions of the equations by creating the energy conditions the equations describe, and then observing how light behaves in those conditions. An equation might predict that light shot through a certain kind of opening will behave one way, while light shot through another opening will behave another way. They photograph the different behaviors, and when the photos correspond to the predictions of the equations, then the equations are verified and the behavior is named. It gets a name like electron, muon, meson, kaon, and so on down the line. As we speak, physicists have set up conditions they hope will verify the existence of a particle called the Higgs boson which, if shown to exist, would verify that empty space is made of a behavior of energy.
These behaviors are going on right now as you read. They are the energies in the paper and ink, on the computer screen, inside your eyeball, whirling away in your brain tissue, right now. Your skin, bones, books, brothers and love of music are all energies behaving in certain ways. Energies causing the sun to combust.
That world of the behavior of energy is so radically different from our world of trees and stones that it can’t even be talked about, except in mathematical equations or in metaphors like the solar system atom.
So far there are no equations or photographs of your thoughts or your love of your friends and family. There is a lot of firsthand evidence they exist, though.