Results 1 to 15 of 15
-
2019-09-26, 09:32 PM (ISO 8601)
- Join Date
- Jan 2013
- Location
- Arkansas, U.S.
- Gender
How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
I get that it's not really supposed to make sense, but I can't even do the math. I don't get it. Not even to the extent that I'm expected to. I've met teachers who, in response to me saying "I don't get it" just tell me "I know it's confusing and doesn't make sense", but still expect me to solve the problems they give me. I can't. I've tried, but I don't even understand the questions I'm being asked, so how on earth can I answer them? Especially when their explanations are completely unhelpful.
I can't even drop the class and start over- this is my last chance, and if I fail, that's it. Pass or fail, by next year, I'm done.
I don't want to fail, but I'm not even sure if I care about any of this anymore. I wish I'd never become a chemistry major, then I'd never be stuck in a class I genuinely don't feel like I belong in.
"What are 3 factors that someone knowledgeable in Heisenberg's Uncertainty Principle could use to argue their way out of a speeding ticket?" to paraphrase the question I'm looking at...
Something about different values for planck's constant that might help too... I don't know this stuff. He brought it up in class, and I drew blanks then.
The entire practice exam is filled with questions like that... and that first one constitutes a huge portion of the credit.Last edited by MonkeySage; 2019-09-26 at 09:41 PM.
-
2019-09-27, 12:00 AM (ISO 8601)
- Join Date
- Oct 2014
- Location
- Tulips Cheese & Rock&Roll
- Gender
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
The Heisenberg speeding ticket joke usually goes something like: "You know how fast you were going there?" - "No, but I know exactly where I am". Because Heisenberg's uncertainty principle is that you can't ever know the exact location as well as the exact speed of a particle. It makes no sense at the scale of a car, none at all, much less even than the one about talking yourself out of a ticket for driving through a red light by arguing it blueshifted to green. At least that one would be possible using a space ship the size of a car if it could go fast enough with a bright enough traffic light (in open space, for some reason...). So I honestly feel like they want you to write 3 variations of this, like "No, I was looking at my navigation. It's very precise."
As for the serious questions, I can't really help you there. So I'll leave you with my number one tip for exams in general, which might help a little: write a cheat sheet. (Quick show of hands: who at this point believes I work at a school? ;).)
Write down every formula you're supposed to know, every principle, the basics of how your calculations work, cram it all onto two sides of the same sheet of paper or so. Grouped by topic, if possible. You now no longer need a cheat sheet, because by writing it down you've learned this core information, at least well enough that you can have it in your head at the exam by rereading this piece of paper in the half hour before it. Being able to apply the knowledge is a whole different thing, but you know, baby steps...Last edited by Lvl 2 Expert; 2019-09-27 at 12:01 AM.
-
2019-09-27, 12:13 AM (ISO 8601)
- Join Date
- Dec 2009
- Location
- Washington D.C.
- Gender
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
Cuthalion's art is the prettiest art of all the art. Like my avatar.
Number of times Roland St. Jude has sworn revenge upon me: 2
-
2019-09-27, 12:28 AM (ISO 8601)
- Join Date
- Aug 2008
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
There's a few specific things you'll want to study up on. Spherical coordinates, differential equations, matrices. P-Chem is a pretty math heavy class, and you want to have the math under control.
I would really like to see a game made by Obryn, Kurald Galain, and Knaight from these forums.
I'm not joking one bit. I would buy the hell out of that. -- ChubbyRain
Current Design Project: Legacy, a game of masters and apprentices for two players and a GM.
-
2019-09-27, 12:52 AM (ISO 8601)
- Join Date
- Jan 2013
- Location
- Arkansas, U.S.
- Gender
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
The first exam is monday, and I'm not even close to ready for it. I don't think I can get help either. I'm trying to study for it, i'm working on the practice exam... problem is, it's not just formulas. it's like this question i've got in the book: "Energy is inversely proportional to the square of the length of the box. How do you account for this dependence in terms of Heisenberg uncertainty principle?"... To me this makes no sense because I see that HUP: dEdt = dxdp. I don't see an inverse relationship here, i see a direct relationship.
Ok, here's what I see: Lots and lots of greek letters, and I have a lot of difficulty finding what they're all supposed to mean. I failed Modern Physics, big time.
The teacher goes over so much complex looking math, so quickly, and I got lost weeks ago. I can't ask questions because I don't even know where to start. We went from something easy enough to understand- wavelength, energy, etc, stuff that wouldn't be out of place in other chemistry classes, then went straight into quantum mechanics and I got completely lost.Last edited by MonkeySage; 2019-09-27 at 12:58 AM.
-
2019-09-27, 01:02 AM (ISO 8601)
- Join Date
- Aug 2008
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
So, there's a few things you should look at here. The mention of the length, singular, of the box suggests that you're looking at a one dimensional system. The mention of the box, singular, suggests that you must be looking at a 1-box system. That'll be a model that you've probably studied specifically, so look at your notes for that particular model.
I would really like to see a game made by Obryn, Kurald Galain, and Knaight from these forums.
I'm not joking one bit. I would buy the hell out of that. -- ChubbyRain
Current Design Project: Legacy, a game of masters and apprentices for two players and a GM.
-
2019-09-27, 01:08 AM (ISO 8601)
- Join Date
- Jan 2013
- Location
- Arkansas, U.S.
- Gender
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
My notes are skeletal and confusing. I can't read my own notes, because I write them down while trying to keep up with him... He does post his notes online... eventually, once every couple weeks he'll dump the entire week's worth, without context. And considering that his handwriting is somehow worse than my own (I didn't think that was possible), I'd actually need him to translate them for me. He may as well give the entire lecture twice.
We did go over one dimensional particle in a box, and I just left that lecture not knowing what the lecture was about.
I assumed that L = dx, so for some reason En = n2h2/8mL2, but energy x time = distance x momentum? that looks like a contradiction.Last edited by MonkeySage; 2019-09-27 at 01:12 AM.
-
2019-09-27, 01:14 AM (ISO 8601)
- Join Date
- Jul 2010
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
Since the exact nature of what you need to know depends on exactly how your professor is running this class, the main thing I think can help is intensively studying with other students in the same class. Ask them lots of questions. Get them to explain things to you.
It'll help them learn the material better as well, since explaining and teaching helps people to learn and understand topics like this.
Also, with regards to the math, I hope you have a solid understanding of linear algebra. A lot of the math in intro quantum mechanics boils down to applied linear algebra.
-
2019-09-27, 02:49 AM (ISO 8601)
- Join Date
- Oct 2014
- Location
- Tulips Cheese & Rock&Roll
- Gender
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
The Hindsight Awards, results: See the best movies of 1999!
-
2019-09-27, 02:51 AM (ISO 8601)
- Join Date
- Aug 2013
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
This isn't going to be very helpful I'm afraid.
This here are major problems. And you are clearly letting slip stuff you can't afford to.
1) Get a laptop? Between spellcheck, autocorrect and such might get most words right, most importantly, at least you can tell what the letters are.
2) Posting notes once every couple of weeks does not cut it. You or someone else needs to talk to this guy. Why does his handwriting matter at all? It's the frickin' computer age. If nothing else, not having to rewrite notes for each class should appeal to the teacher. We managed to get the national economy prof to stop using his jampacked overhead slides (about 20 or 30 years of service in those) somewhere just after the millennium changed. Powerpoint people! (as an aside having a fixed written text might make the teacher stick closer to a good logic path, sometimes it's easy to wind off that when you know a lot trying to cram it all out) Also should mean you can get notes fresh off class instead of when you've started to forget.
3) You might need to read ahead before each class. Get familiar with what's coming up at least in passing. Basically don't show up as a blank slate.
4) Don't leave a lecture not knowing what it was about. You need to pester the teacher. Or afterwards ask for some easier way to understand it or something. I get the feeling you are leaving it to far too late to try and catch up to gaps. It should not be in the teachers interest to elt students fail (though some of th epeopl who get tenure...).
5) Have a cow man, the proteins are good for learning(I'm joking)
In highschool and college I was a straight A student in math. Until the course on derivations. I could do the formulas well enough. But the second there was a question that was just a wall of text I realised I had no idea what I was supposed to do. Yeah there was a derivation in there somewhere, but I'd be darned if I knew what it had to do with a barn.
-
2019-09-27, 03:46 AM (ISO 8601)
- Join Date
- Aug 2008
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
That does, however, give you a key thing to look up elsewhere - the phrase "one dimensional particle in a box". Look that up online, and suddenly there's plenty of information. You also have that equation; textbooks will generally take pains to define the meaning of the variables involved in the text somewhere.
I would really like to see a game made by Obryn, Kurald Galain, and Knaight from these forums.
I'm not joking one bit. I would buy the hell out of that. -- ChubbyRain
Current Design Project: Legacy, a game of masters and apprentices for two players and a GM.
-
2019-09-27, 09:48 AM (ISO 8601)
- Join Date
- Mar 2010
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
For a question like that you write up all you know about the uncertainty principle. Then you can read that and try to determine how it could apply to speeding tickets. Realistically the link to the speeding ticket aspect isn't what they're looking for it at all. They just want you to write out what you know about the uncertainty principle and some manipulations of it to relate to SOMETHING.
-
2019-09-27, 12:44 PM (ISO 8601)
- Join Date
- Jan 2009
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
I second a study group with other students. Maybe even offer to buy a pizza or something to entice some folk to join you. I think my university had something where I could send an e-mail to the other students in my class, so even though it's Friday and the exam is Monday, you might be able to reach and get in touch with some fellow students.
I also think it'd be worth asking the professor to be more prompt and clear when sharing notes. Between now and the next exam, try to meet with him to go over questions you have, or see if there's a tutor/help thing that the college's grad students have to do. (I never wound up using it, but I was comforted knowing I could take my calculus questions to the math department's "helpdesk" while I was doing my statistics degree.)
---
One other thing that might help morale: consider how low a grade you can get and still pass the class, assuming you do decent (like Bs) in the other assignments. One time I was unsure about how I'd do on a final, but I realized I could get a 70 and still pass the class. That really helped my stress levels and let me be more focused for studying and the exam.
-
2019-09-28, 01:18 PM (ISO 8601)
- Join Date
- Jan 2006
- Location
- Protecting my Horde (yes, I mean that kind)
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?
-
2019-09-30, 03:32 AM (ISO 8601)
- Join Date
- Aug 2013
Re: How can I pass Physical Chemistry if quantum mechanics is gibberish to me?