Table of Contents
What is Quantum Physics?
Why Should I Care About Quantum Physics?
Vocabulary and Other Important Stuff
Keep an Open Mind! (Read Me! Read Me! I'm Important!)
"Let's start at the very beginning. That's a very good place to start". Let's follow Julie Andrew's advice and clear up a few things before we delve into the heart of the subject. In order to understand the basic concepts of quantum physics, we must first understand a few basic concepts of physics. It’s also good to know a little bit of vocabulary (Don't worry, you can always refer back to this section so you don't have to learn it by heart!) and a little bit about what quantum physics really is. Even if you are already familiar with quantum physics, I suggest you look at the “Vocabulary” and "Keep an Open Mind" sections, just so we're all on the same page. An asterisk (*) indicates a note or comment at the end of the section.
You might have heard about Albert Einstein's Theory of Relativity*. That's good. You might also have heard that this theory explains everything in the universe. Unfortunately, that's not true. In fact, Relativity explains everything that is big: from solar systems to particles of sand! (Yes, they're considered big too ... at least in the realm of quantum physics!). But while Einstein's theory has yet to be faulted when we're talking about the "big stuff", it falls apart when we try to apply it to little things (like electrons, quarks and other subatomic particles). That's where quantum theory comes in. Quantum Physics explains (or tries to explain) the movements and interactions of atoms and subatomic particles.
The answer to this question is quite simple: quantum physics is important because it explains the basis of our entire world. It explains what we're made of, where we come from, what happened in the very beginning of the universe, why we exist and how we might exist in the future - among other things. Obvious - right? Well, not all that obvious, because that still doesn't explain why you would need to know it. That's great for scientists, but why should "normal" people take time to learn it? Personally, I'd be tempted to simply answer “curiosity”, but again, that doesn't always justify the time and effort you have to put in to understand quantum physics. So here are a couple "motivational reminders", just to keep you going (or get you started!)
Fermion: A fermion is a type of subatomic particle. Usually referred to as matter particles, fermions have a half-integer spin (see below) and contain an odd number of quarks and or leptons. Protons, neutrons and electrons are fermions. This type of particle obeys Pauli's exclusion principle (see below).
Boson: A boson is a type of subatomic particle. Usually referred to as force carriers, bosons are not made of matter (therefore, they have no mass). They have an integer spin (see below) and contain an even number of quarks and/or leptons. Photons and gluons are bosons. This type of particle obeys the Bose-Einstein Statistics (see below).
Spin: Spin is one of the many characteristics that we use to distinguish one particle from another. A Half-Integer spin is a spin that we describe with numbers like -3/2, -1/2, 1/2, 3/2, 5/2, etc. An Integer spin is a spin that we describe with numbers such as -1, 0, 1, 2, 3, etc. As for the specifics, you don't really need to know them in order to understand anything you'll find on this site, but if you're curious, there are many other websites out there you could check out.
Photon: Boson which makes up light. The photon has no mass is usually represented by the Greek letter gamma (γ).
Plank's constant: Represented by the letter h, Plank's constant is a very, very small number ( something like 6.626068 × 10E-34 to be precise). It represents one quanta, or lump.
Volume: Volume is how much space something occupies. It is usually made up of three dimensional measurements. For example, if I want to give the volume of a die that measures 2cm x 2cm x 2cm, I would say it had a volume of 2x2x2 or 8 cm3. Raising the units to the third power shows us that there are three measurements being multiplied, or three dimensions being considered.
Coordinate Grid: A coordinate grid is an imaginary set of lines that intersect in a crisscross pattern. It can have any number of dimensions, but is usually used to chart two or three-dimensional space. Each line represents a number and the distance between each line is equal. The numbers that the lines represent and the difference between these numbers is arbitrarily determined, but must stay constant throughout the grid.
Mass: Mass is different from weight. This is the first thing to understand. Weight can vary, depending on gravity, mass is constant, always. In short, mass is a measure of how much matter everything around us is made up of and weight is a measure of how much gravity pulls on that matter. Weight is measured in newtons while mass is measured in kilograms, or pounds.
Pauli's Exclusion Principle: Pauli's exclusion principle applies only to fermions. It states that no two identical fermions can occupy the same quantum state.
Keep an Open Mind! (Read me! Read me! I'm Important!)
Here are a few things to keep in mind while reading this website. These thoughts are very important because the key to understanding is believing you can understand it and keeping an open mind.