Electrodynamics Tutorial Series/Intro

Topics Covered

• Format of the series
• Requirements
  • Calculus
  • Basic Physics (Newtonian Mechanics)
  • Griffiths Introduction to Electrodynamics
• What to Expect
• Broad topic discussions
• Why it's hard
• Why it's fun
• Why it's useful

Script

<Me, standing up in front of a whiteboard with "Electrodynamics!" and other doodles>

Hi, I'm Jonathan Gardner, and we're going to learn electrodynamics.

Normally, people would wave their hands and smile and help you try to grasp what's really going on. I'm not going to do that. We're going to learn this subject the same way a physicist would.

Although there's a lot of math, it's not hard, and you'll actually feel smarter.

Take your time, review material often, and try to learn something new everyday.

Requirements: You should have a good grasp of algebra and calculus. If you don't, that's ok, but you'll have to be willing to learn. You should also understand basic physics, such as Newtonian mechanics. If you don't, you can probably make it, but again, you'll have to be willing to learn.

You'll need to get Griffith's Introduction to Electrodynamics. There's a link below in the description. Support Griffiths and encourage more great physics textbooks like his by actually spending your money on this, even if you can't afford it.

Most of all, you need an open mind. You are smart enough to grasp this. Your brain may need some time to catch up, but if I can learn this, so can you!

What do I promise? I promise to cover the material in Griffith's "Introduction to Electrodynamics." I promise to broaden your understanding of how math and physics works together. I promise to show you why *real* physics is fun and interesting. And most of all, I promise you'll be much smarter than you were before you started this course.

Electrodynamics is made up of two word-parts: electro, that having to do with electricity or lightning, and dynamics, meaning how things change and what that means. This is an interesting topic because by studying how electricity and magnetism really works, you can find the math behind God's statement, "Let there be light." Also known as, Maxwell's Equations.

Show Maxwell's Equations.

Nod knowingly.

And there was light!

Scene change. Now the board shows the four squares of physics, as from Griffith;s book. The four forces are also listed.

Physics can be divided into 4 areas, having to do with how small or how fast things move. The world we live in everyday is the world of Newtonian Mechanics. If you go really fast, then you have to think about Relativity. On the other hand, if you shrink down to the size of sub-atomic particles, then you are in the quantum world. And if you go really fast and think about small things, then we're talking about Quantum Field Theory.

Electrodynamics works in all four areas, without any changes. If you think about it, it was electrodynamics that showed us how to get from our everyday world to the quantum and relativistic worlds. Light is, after all, and electric phenomena.

Another way to look at the universe is to think of the four forces that drive every phenemenoa we have ever observed. The strong force is what binds protons and neutrons to themselves and into atomic nuclei. The electromagnetic forces are what keeps the electrons near the nucleus. The weak force is much weaker than the EM force, and it drives certain kinds of radioactive decay. Gravity, the first force you probably noticed, but by far, the weakest of them all, is what keeps our feet on the ground and the planets orbiting the sun.

What about friction, and normal forces, and drag? Fundamentally, these are all electromagnetic interactions. There are particles pushing and pulling on each other because they have electromagnetic repulsion and attraction, when you get right down to it.

Of the four forces, we understand electromagnetism the best. As physicists grew to understand what electricity really was, and how magnetism was really a manifestation of the same thing, and as we've grown to understand how electric the world around us really is, we've tried to make the strong, weak, and gravitational forces just as well understood. We are not there yet, unfortunately.

You can read the "Advertisement" in Griffiths. He shares more details and is far more precise than I ever could be. So take some time after this video to read the section yourself.

As homework, your assignment is to think about how awesome you're going to be when you truly understand the electromagnetism that is all around us. Wave to your future self and smile as he waves back. Yes, your journey to really understanding what this is all about begins right now.