 Atoms are unbelievably small. So small that they were once thought to be the smallest unit of matter. That is, until some recent advancements in particle physics came along. The atom, as most of you watching this video know, is made up of three primary parts. The positively charged proton, the neutrally charged neutron, and the negatively charged electron. The electrons, which orbit the atom, are leptons, which are also known as fundamental particles or particles that are not made up of any other smaller particle. However, what's more interesting about the electrons is that they possess a property called a wave function. To understand what the wave function is, let's just say I wanted to know the location of an electron orbiting around the atom. Unfortunately, the baffling laws of quantum mechanics prevent me from knowing the exact location of an electron at a given point in space at any given moment in time. However, the wave function tells me the general area of space where the electron is most likely to be at any given moment. Still not clear enough? Then let me give you another example. Let's say we have a box with four corners, A, B, C, and D. Now, let's say I put an electron in the box and put a lid on the box and then let the electron freely bounce around in the box while I hooked up the box to a supercomputer which would try to locate the electron inside the box. Now, when the computer starts to give you the location of the electron, you'd expect a very specific answer like the electron is located three inches away from the left side or six inches away from the right side, etc. But that's not the answer you would get. Now, obviously the results which you just heard are just exaggerated for the sake of this video because in real life you probably would not get results like that. Instead, you'd probably get results like this where the high concentration of dots indicate where the electron is most likely to be found inside the box and the low concentration of dots indicate where the electron is least likely to be found inside the box. So, basically in a nutshell, the wave function just tells you where the electron or any subatomic particle is most likely to be found at any given moment in time. So, now that we're done talking about the electrons, let's now take a look at the protons and neutrons that make up the atomic nuclei. Now, protons and neutrons are hadrons or a class of subatomic particles that are made up of even smaller subatomic particles called quarks and gluons. Now, as far as we know in our universe there exist six types of quarks. The down quark, the up quark, the strange quark, the charm quark, the top quark, and finally the bottom quark. Protons are made up of two up quarks and one down quark. Neutrons, on the other hand, are made up of two down quarks and one up quark. Now, we can understand how quarks interact with each other through produced particles like protons and neutrons through a process called quantum chromodynamics. As you can see, all six quarks have one of three types of charges which physicists describe using three primary colors, red, green, and blue. In order to create a particle, one red, blue, and green quark must combine to create white, which would be an electrically neutral particle like a neutron. So, in short, that's the basics of quantum chromodynamics. The world of atoms is really weird. It's so weird that the laws of physics that govern the world of atoms are completely different from the laws of physics that govern our everyday lives. So, now there might be some questions going through your head like, what's smaller than a quark? And for those of you who are watching this and already know a little bit about quantum mechanics, you're probably thinking, why hasn't he talked about Schoediner's cat or the theory of everything? That's because those principles of quantum mechanics are so awesome that they deserve their own videos. So, if you want to learn more about the wacky quantum realm, then subscribe for more science videos.