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1 point

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30th Sep 2021

You might want to take some time and read Feynman's presentation.

I'm fairly confident my post summarizes his approach.

Remember it was Feynman who gave the teams at Stanford a conceptual model they could understand. That understanding led them to prove the existence of quarks. The guy was no dummy.

1 point

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30th Sep 2021

I didn't say the glass absorbs photons. I said the electrons either absorb or emit the photons.

> A more appropriate description is that the electrons in the glass are perturbed by the incident light... You're describing electrons absorbing photons.

"My explanation" isn't mine. It's Feynman's. Rather, it's my gross simplification of his 4, 1 hour lectures. It's a particle-centric explanation instead of wave-centric explanation and is a hell of a lot easier to understand as to what's going on.

You can cite all the Internet sources you want but Feynman literally wrote the book on QED. Well he, Schwinger and Tomonaga did. Schwinger's approach was supplanted by Feynman's. His diagrams made renormalization computation far easier to the point that Schwinger moaned Feynman had made renormalization too easy.

1 point

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30th Sep 2021

The short answer is electrons absorb and emit photons as photons travel through matter. The direction the photons are emitted is a probabilistic function of the photon's energy. If the absorbed photon didn't have enough energy to make the electron change orbitals, the emitted photon most likely be emitted in a certain direction. If the absorbed photon did have the requisite energy for the electron to jump, then when a photon is eventually emitted, it'll be in different direction.

The idea that glass is transparent to visible light because the light doesn't have enough energy to be absorbed by electrons in the glass is wrong. The photons are being absorbed and emitted willy nilly, but the most likely direction the photons are emitted is in the same direction the absorbed photons were initially traveling. This interpretation explains why some photons are reflected, why the optical clarity of glass varies sinusoidaly and indefinitely as you thicken glass, why light travels more slowly in glass than it does in vacuum and a host of other aspects.

Richard Feynman, a physicist who won a Nobel prize for inventing a technique for computing how electrons and photons interact, gave a series of four lectures in 1984 that describe the process in laymen's terms. The lectures are available here Be prepared to be surprised by what he said, it's not the usual stuff you stumble across around the net or many college lectures. Thing is, his computational techniques and diagrams are what are used.

1 point

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15th Apr 2018

First of all I will say that no matter what you look at, physics is one of those things where you can never be "correct" per se without understanding the math. That goes double for QM which is math all the way down. No matter how you explain it, you will always find that "but what about this exception" can be answered to your satisfaction only by getting a mathematically rigorous treatment of the topic.

That said, for understanding quantum on a "fun" level (i.e. skipping a couple of years of calculus, linear algebra, and numerical analysis), I'd recommend Richard Feynman's QED: The Strange Theory of Light and Matter. A very well-known and highly respected physicist with a talent for teaching. Although "quantum electrodynamics" as covered in the book is not strictly QM as generally imagined, he does cover the core of what is at interest in quantum theory (electromagnetic interactions at a subatomic level) in a pretty interesting and decently understandable way. That sounds like about what you're looking for.

2 points

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29th Jul 2021

I'm also from Canada and started getting into physics around your child's age. (I'm now a grad student.)

If he's interested, you should get him *both* popular books and a good introductory textbook. I can't speak as to other provinces, but the physics curriculum in Ontario leaves much to be desired. For this reason, I think it's worth self-studying physics if he's interested. Irrespective of whether he pursued physics as a career, the skills you acquire from doing physics carry over to many different fields, and (more importantly) it's fun!

You've already received many good recommendations for popular books - I'll add QED: the strange theory of light and matter, by Feynman. Here's a link to it on Amazon.

As for textbooks, I'd get him a nice book on calculus and any introductory physics text. I learned calculus from this book, which is intended for self-study. It's a pretty old book, but it's great.

A bunch of good youtube channels have already been brought up in this thread, and the only one I'll add is 3blue1brown, who makes some beautiful and accessible videos about math.

2 points

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10th Apr 2019

I'm no physicist. My degree is in computer science, but I'm in a somewhat similar boat. I read all these pop-science books that got me pumped (same ones you've read), so I decided to actually dive into the math.

​

Luckily I already had training in electromagnetics and calculus, differential equations, and linear algebra so I was not going in totally blind.

​

I've been at it for about a year now and I'm still notwhere close to where I want to be, but I'll share the books I've read and recommend them:

- First and foremost, read Feynman's Lectures on Physics. You can find them free on the link there, but they also sell the 3 volumes on amazon. I love annotating so I got myself physical copies. These are the most comprehensible lectures on anything I've ever read. Feynman does an excellent job on teaching you pretty much all of physics + math (especially electromagnetics) up until basics of Quantum Mechanics and some Quantum Field Theory assuming little mathematics background.
- Feyman lectures on Quantum Electrodynamics(The first Quantum Field Theory). This is pop-sciency and not math heavy at all, but it provides a good intuition in preparation for the bullet points below
- You're going to need Calculus. So if you're not familiar comfortable with integral concepts like integration by parts, Quantum Mechanics will be very difficult.
- I watched MIT's opencourseware online lectures on Quantum Mechanics and I did all the assignments. This gave me what I believe is a solid mathematical understanding on Quantum Mechanics
- I'm currently reading and performing exercises from this Introduction to Classical Field Theory. I'm doing this in preparation for the next bullet-point:
- Quantum Field Theory in a Nutshell. Very math heavy - but thats what we're after isnt it? I havent started on this yet since it relies on the previous PDF, but it was recommended in Feynmans QED book.
- I've had training on Linear Algebra during my CS education. You're going to need it as well. I recommend watching this linear algebra playlist by 3Blue1Brown. It's no substitute for the rigorous math, which I learned through this book. But my life would've been a lot easier if that playlist existed before i took my linear algebra course, which was taught through this book.
- Linear Algebra Part 2 - Tensor analysis! You need this for General Relativity. This is the pdf im currently reading and doing all the exercises. This pdf is preparing me for...
- Gravity. This 1000+ page behemoth comes highly recommended by pretty much all physicist I talk to and I can't wait for it.
- Concurrently I'm also reading this book which introduces you to the Standard Model.

​

I'm available if you want to PM me directly. I love talking to others about this stuff.

1 point

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27th Mar 2018

I think plank length is way too small. The size ratio between plank length and proton is something like the size ratio of proton to solar system, give or take a couple orders of magnitude. Plank length is like 30+ orders of magnitude smaller than a proton or something IIRC.

Chemicals (i.e., outside of the nucleus) repel because of photons emitted from and absorbed by nearby electrons. Here's a couple of fun layman-level mostly-math-free books on the topic, if you care to learn more:

https://smile.amazon.com/QED-Strange-Princeton-Science-Library/dp/0691164096/ref=sr_1_1_twi_pap_1

https://smile.amazon.com/Quantum-Universe-Anything-That-Happen/dp/0306821443/ref=sr_1_1

(Get the paper copies. The illustrations are unreadable on ebook readers.)

Or, if you prefer fun videos, https://www.youtube.com/channel/UC7_gcs09iThXybpVgjHZ_7g

1 point

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4th Nov 2016

Indeed!

https://smile.amazon.com/QED-Strange-Princeton-Science-Library/dp/0691164096/ref=sr_1_1

https://smile.amazon.com/Quantum-Universe-Anything-That-Happen/dp/0306821443/ref=sr_1_1

https://smile.amazon.com/Why-Does-mc2-Should-Care/dp/0306818760/ref=sr_1_1

https://smile.amazon.com/Our-Mathematical-Universe-Ultimate-Reality/dp/0307744256/ref=sr_1_1

If learning actual physics isn't your thing,

https://www.youtube.com/watch?v=J3xLuZNKhlY

https://www.youtube.com/watch?v=Ztc6QPNUqls

https://www.youtube.com/watch?v=3LyFap2aUN0

https://www.youtube.com/watch?v=7ImvlS8PLIo

Basically, if things only *probably* don't exist, then they come out of nothing with some probability. If you want to consider it impossible for them to not come out of nothing, then there's no such thing as "nothing," so arguing that "something can't come from nothing" is like trying to draw conclusions from the observation that there's no such thing as a *white* unicorn.

The normal expression of "you can't get something from nothing" isn't really about quantum physics or the start of the universe. Taking that expression as obviously true when talking about such things so far outside of normal common sense experience is not obviously true in the same way it would be if you said "You can't take a cookie from an empty cookie jar."

Also, I didn't say the statement is neither true nor false. I said making an argument of the form "If X then Y" when X is never true is not a useful argument to make. It conveys no information. Regardless of what you substitute for X or Y, you cannot from that conclude panpsychism is supported.

1 point

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2nd May 2016

1 point

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19th Dec 2015

To quote Richard Feynman >"...there is also an amplitude for light to go faster (or slower) than the conventional speed of light. You found out in the last lecture that light doesn't go only in straight lines; now, you find out that it doesn't go only at the speed of light! It may surprise you that there is an amplitude for a photon to go at speeds faster or slower than the conventional speed, c."

When Feynman said "amplitude" he meant "the square of the probability of an event." The above quote came from a series of lectures he gave at UCLA that were subsequently published.

1 point

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17th Dec 2015

If you're looking for a good lay explanation, start here: QED: The Strange Theory of Light and Matter. Nice short book by Feynman.

1 point

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8th May 2015

If you want the long and complete answer, read QED: The Strange Theory of Light and Matter (Princeton Science Library by Richard Feynman. Fascinating stuff that will melt your mind.

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