I remember in my physics classes we literally dedicated two weeks to learning about units. This was in the sophomore level physics and I remember thinking(wtf this is dumb, I already know how units work oh well easy points xD)
But I’m starting to learn how useful that was. It really helped in doing long problems because you intuitively run through your mind if your units work. You also become a lot more natural at special cases, because you know conceptually how the problem works, so mathematically you can eliminate stuff if you let one variable go to infinity or 0 and it doesn’t behave like it should be.
I’m doing a practice Physics GRE and to tell you the truth some of the questions I don’t even really have to do the physics. Some of the multiple choice questions I can eliminate because the units just plain don’t match up. The others I can do that special cases analysis and see how it goes to infinity with a variable and the problem takes less than a minute to solve.
It’s great for the GRE but also useful in science because who wants to go back and do 30 minutes of useless work. I do wish courses did unit analysis a lot more and I realize that time we spent was some of the most useful stuff we learned
I agree. Unit analysis/dimensional analysis is one of those topics that gets covered early on and almost everyone thinks it’s stupid. I’m also a physics major, and I’ve come to realize just how important it is. As you say, it helps a great deal when solving problems if you already know how the units should work out.
I’m not sure if this is really a topic that needs to be repeatedly covered though. It’s more about developing an intuition for what units are and how they work. Derivations of equations involve applications of dimensional analysis almost by default. Our textbooks might not have sections within the chapters devoted to the relevant dimensional analysis, but they’re still using dimensional analysis within the books every time they work a problem or derive an equation.
Alright dude this sounds weird, but I recognize you. I saw your post on a facebook comment about getting a reserach/internship at FermiLab or CERN or something in one of the physics facebook pages I go to and you were the top comment. I recognize your profile picture as your avatar.
I’m a senior in HS but I feel like my understanding of chemistry/physics became much greater after I understood dimensional analysis/unit analysis. I had no idea why stoichiometry is done the way it is done; at first I thought it was really redundant and I was like “I’m good, I can just do this in my head”. That eventually got to me, and behind tons of mental math mistakes, sig fig mistakes, and not fully understanding the units, I forced myself to learn it. And you can see whether or not you did a conceptual error if the units aren’t what they’re supposed to be.
I think they should teach dimensional analysis as soon as they start algebra or any science that uses math. My husband (PhD in physics) and I had a group of mathy kids that we taught dimensional analysis to in 5th/6th grade because they were training for elementary math competitions with lots of word problems. We told them, “this is really useful in the long run; use it; remember it.”
I agree with that. People often struggle with units. After all of the physics an math I’ve taken, I’m very comfortable with them. I also know people that are very good at math but aren’t the greatest with units. People see it as something that’s “added onto” the math at the end or something, but it really is part of the math.
