Anonymous said: may I ask you something, it might be odd and if so forgive me, but you're the only person I know on here who I've encountered that majored in physics, so how do you think like physicists. I ask because I really love physics and studying it but I do very poorly in comparison to my other subjects. if I were better at it I would switch from engineering to physics. thank you for your time.
oh this is a really good question (and not odd at all)
and, this is something that I had to learn in college myself. it’s not something I’m learning much of anymore (but it’s still a skill I’m glad I learned some of). and as a first year student I didn’t quite have a grasp on these concepts.
I should state that more explicitly: you don’t really ever learn to think like a physicist. it’s a process that is always happening.
a good starting point is the Feynman Lectures on Physics, available free at this link
the lectures are from when Feynman taught introductory physics for first years at Caltech, and they are an exceptional resource for learning the basics and getting a qualitative feel for a good way to think about physics.
there are some other things that I personally have noticed from learning physics. im going to avoid talking about computational tips because I don’t know a lot of those and because some of those are advanced and tricky, but computational skills are important.
1) estimation is important. somewhere feynman mentions something about knowing what the solution to a problem will look like before computing the solution.
say: how many bars of soap are used in the united states each year?
I have no idea. but an average number depends on simple things: the population of the US, the percentage of the population that uses bars of soap, the average number of soap bars they purchase in a year, and so on.
from there you can actually just. guess at some of the unknown numbers, and you will get a good order of magnitude estimate. then it might be possible to really do the problem with known statistics, and use your estimate as a guess.
sometimes it’s hard to get an estimate a priori and then you just have to do the calculation, but if you can, it really helps.
2) familiarity is helpful. one of my professors phrased this as “you should know something about the place you live” in reference to the fact that our class didn’t know that the earth was 40 million meters in circumference
let’s not talk about the other multitude of various physical constants I have memorized, sometimes to a terrifying number of decimal places, like h = 6.626E-34 J s
this sort of familiarity is an extension of 1) and knowing what the general size of things is
3) draw pictures. okay, yes, you can’t really do this in quantum mechanics, but when you can draw pictures they are incredibly helpful. a good picture can often solve your problem for you.
especially important here is the idea of symmetry
the symmetry in a problem often can solve things for you (ex: what’s the net gravitational force on a particle at the center of the earth?)
but be careful: sometimes you can draw a picture incorrectly and get incorrect information. so be sure to draw an accurate picture (draw big it helps)
finally: good luck, have fun! :D