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So you want to learn physics (second edition, 2021)

susanrigetti.com

21–30 of 73 posts

Re: So you want to learn physics (second edition, 2021)

#21

I have no idea why these sorts of posts are popular. Past college you're not going to learn physics by trying to self-study an entire university course. The best way to learn is just to pick a small part of physics you'd like to learn (preferably related to your job), i.e. how GPS work or some fluid mechanics etc... Then learn the physics you need for that. Knowledge accumulation can't be organized in a straight line…

I think self-studying a university curriculum is also helpful. I've studied physics at the undergraduate level myself.

Quantum mechanics, for example, is useful enough as a general background, and going through fluid dynamics and GPS problems is also helpful. But if you just follow the application problems, you can learn what you need, but the bigger risk is that you might miss the larger framework that defines those problems. That's not necessarily a bad thing. In fact, the entire university curriculum training is ultimately a process of translating complex phenomena into the Western scientific way of understanding things. It's a mental model that says 'this phenomenon can be interpreted with this kind of formula.'

In other words, it's about building mental models. In a formal university curriculum, you usually learn things like vectors, topological spaces, energy conservation, and how to map real-world phenomena onto these perspectives. It's about learning to simplify the world using mathematical tools. I didn't go to a top university, so I didn't learn things like tensors, but I hear they're taught now. I used tensors in grad school.

Of course, when I actually code and deliver factory equipment, I've done motor-related work under NDA, and the actual formulas aren't always perfectly accurate. There are corrections and adjustments. But the important thing is not just problem-solving itself, but building the mental model of 'how to approach the problem' before solving it. And I think the curriculum helps with that.

Re: So you want to learn physics (second edition, 2021)

#22
I've found pacing to be the biggest problem with self-learning of academic subjects.

Suppose we are learning from a textbook. The things we learn in each chapter are built upon in the subsequent chapters. If we go forward before we have a good enough understanding it can make it very hard to learn that next chapter.

On the other hand if we wait to go forward until we feel we really have mastered the material up to this point it can take a long time to move forward, and that doesn't even really gain you anything.

The best way to master something is to practice it. The textbook author knows this. The author writes each chapter under the assumption that you are OK with the material from the previous chapters but have not yet mastered that material. You now need things to practice that material on, and using it while learning the material of this chapter is perfect for that.

That point where you have gotten good enough with the present material that you can handle the next chapter is almost certainly going to be a point where you do not think you are ready.

Re: So you want to learn physics (second edition, 2021)

#26

I have no idea why these sorts of posts are popular. Past college you're not going to learn physics by trying to self-study an entire university course. The best way to learn is just to pick a small part of physics you'd like to learn (preferably related to your job), i.e. how GPS work or some fluid mechanics etc... Then learn the physics you need for that. Knowledge accumulation can't be organized in a straight line…

Let's subject that claim to some basic arithmetic. A university would expect maybe eight undergraduate level courses, four credit hours per course, and you are expected to do three hours of study per hour of credit per week. That's 1,500 hours. How does that compare to the "hours played" on a typical strategy game Steam review?

much less dopamine, video games are realy good at stimulating that. Studying physics not so much.

Don't get me wrong Physics can be satisfying in its own ways but the amount of dopamine rushes you get from cracking a hard problem are few and far between. Often enough you just get frustrated and once you find the solution you think to yourself oh is that easy how didn't i get that before and feel absolutely stupid.

Re: So you want to learn physics (second edition, 2021)

#29

I have no idea why these sorts of posts are popular. Past college you're not going to learn physics by trying to self-study an entire university course. The best way to learn is just to pick a small part of physics you'd like to learn (preferably related to your job), i.e. how GPS work or some fluid mechanics etc... Then learn the physics you need for that. Knowledge accumulation can't be organized in a straight line…

I'd disagree and have done exactly that. I started with a reasonable basis in physics, but self studying through an entire course dramatically expanded my understanding. For an example of what I mean this [1] is Feynman's lecture on conservation of energy. It's something every schoolkid learns -- I'm fairly sure I saw my first pendulum from the nose demo in middle school, yet Feynman will take this and make you compl…

Conservation of energy is simply the invariance of a system to translation in time: the system shows the same time evolution from a well defined starting state regardless of whether that state exists at a time t or a time t+t' with an arbitrary t'. This is one application of Noether's theorem.

This is an example of a topic that unstructured self study would likely skip. But it is included in every properly structured course because this theorem puts a fundamental explanation to all conserved quantities that occur in classical mechanics.

Re: So you want to learn physics (second edition, 2021)

#30

I have no idea why these sorts of posts are popular. Past college you're not going to learn physics by trying to self-study an entire university course. The best way to learn is just to pick a small part of physics you'd like to learn (preferably related to your job), i.e. how GPS work or some fluid mechanics etc... Then learn the physics you need for that. Knowledge accumulation can't be organized in a straight line…

> I have no idea why these sorts of posts are popular. Past college you're not going to learn physics by trying to self-study an entire university course.

You have no idea, because you have no motivation or interest to self-study.

But if you pay attention, you will notice that your personal motivation and interest does not match the ones from all the people engaging in this discussion.

The reason why this sort of topic is popular is because others have different interests, motivations, and ability to do it.

You should not spend time trying to convince others that they cannot, and instead you should look inside and see what you can do for yourself.

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