This class is very frustrating. Dr. Weiss was so busy and had no time to prepare the lectures. As a result, the lectures deviated so far away from the course description. It's a total waste of time to go to the lectures.

I loved this class. My friend and I referred to it as "Storytime" because every one of his lectures was just him talking about funny stories and things about chemistry he thinks are interesting. That made the class super interesting and easy to make yourself go to. He's a funny little dude and what he teaches, he teaches well. However, he teaches pretty much none of the course curriculum, leaving that to the homework problems. So if you want to actually learn 20B, don't take him. But if you want to enjoy the class, Weiss is your man. You hardly need to take notes if you pay attention to the lectures and go to review sessions before tests. The tests aren't hard at all if you do that, plus there is a ton of extra credit available. It's annoying that he gives a ton of homework and it's due every lecture, especially since it's always on topics totally separate from the lectures. But all the test material comes from the lectures, not the homework, so it's not a huge deal. Overall, there's more work than there should be and you won't learn anything that you're supposed to, but it's super easy and even more interesting. I would recommend this to anyone who needs to take 20B but isn't any form of Chemist.

We can see some pretty words coming from the latest review, praising Prof.Weiss for the "challenge and tests that conceptually prod your understanding of chemistry to previously unattained depths". Indeed, the materials covered during lectures are interesting and unprecedented. However, I would like to ask the reviewer:

"Did the extra course materials compensate for the loss in materials that were supposed to be taught but not covered in lectures?"

No they didn't. Weiss didn't really discussed much about thermodynamics, acid-bases, or equilibria. As a result, you have to study them on your own by referring to the textbook, which is indeed poorly written.

As an introductory course, chem 20b is designed to prepare undergraduates for their even tougher upper division chem/engineering courses. Thanks to Weiss, I can say that over 60% of the class became underprepared.

I do not want him to overthrow this course's original aim.

First off, Professor Weiss loves chemistry and loves teaching it; however, as evident from numerous other reviews, this doesn't always translate to the best learning environment for students.

The class really is structured more like an honors class--which is what he taught for 8+ years at Penn State. Yes, the homework load is heavy and graded hard. Yes, the tests really cannot be studied for and do indeed test your ability to think and reason chemically. Yes, his slides are quite complex and hard to absorb.

BUT, though this class, you can really gain an appreciation for true chemistry that is applicable in the real-world rather than in the crappy book. I am a mechanical engineering student and am actually sad now that this was my last chem class.

I WOULD NOT recommend taking this class if you're looking for an easy, good grade (that's Li). I WOULD recommend taking chemistry with Professor Weiss if you're up for a challenge and tests that conceptually prod your understanding of chemistry to previously unattained depths.

This class is almost entirely about Weiss' nanotechnology research and techniques more than about what supposed to be Chem20B materials. It got three midterms - lowest one dropped, and a final. You will be tested on those research as well, along with some weird grading criteria - it is like grading an essay. There is no calculation on the tests, it is conceptual and confusing - almost like a guessing game. The way he teaches lectures is like research talks, however the students, with very little background knowledge, have to "imagine" of what he is talking about. There are some days lectures will be on Skype, which is not helpful at all. I studied countless hours and still messed up in this class. Paul Weiss is a great researcher and a nice guy, but I definitely do not recommend this professor for Chem20B. Find another professor who will make you love and enjoy Chemistry.

Taking Chem 20B with Weiss was probably the worst thing I've done at UCLA. My motto is "KNOW THE MATERIAL SO WELL YOU CAN PERFORM IT IN YOUR SLEEP". I did that for hos class, too. I did the all-nighters, I put in 60+ hours of study per midterm (3 in his class) enough to make you feel prepared, but no, the midterms were wholly focused on things that shouldn't even be in the 20B syllabus.
He had homework due EVERY lecture, and most times, the TA's would give you 2/3, leaving you with a C average on the homework, which was worth 30% of the total grade.
The final exam included material that did not have anything to do with the course.
Coming from a big time chem lover, if you still want to like chem or even pass it, take it with some other professor. Weiss is a nice man, but you can tell he is more of a researcher than a professor.

Chem 20B with Weiss is very very different than with Li. It's really not fair how different the two classes are in terms of difficulty. Weiss goes over at least three more chapters than Li does and his grades are much lower than compared to Li. That being said, Weiss is a fantastic person and extremely helpful, but his class is very frustrating. There is homework due each lecture, accompanied by around four sections in the book each time. This homework often takes a 1.5-2 hours if you do all the reading. The homework is graded and counts for 30% of the class. While most may see this as a good thing, the TA's almost always handed out 2/3 for the homework, which means you're losing 10% off of your final grade. In addition, the reading and homework have nothing to do with what is covered in lecture. It's like taking two separate courses within one. The homework is mostly equations and numbers-based, while the tests are entirely conceptual. It makes no sense. I can see how a chem or biochem major would enjoy this class, but as an engineer who just wants to fulfill his chem requirements so he can move on, this class was very unenjoyable.
TL;DR Only take this class if you really love chemistry. Otherwise, take Li. Actually, just take Li no matter what.

Professor Weiss has entirely changed 20B from the normal syllabus of the class, he assigns homework and reading from the textbook but after the first month I completely stopped doing the reading because it has NOTHING to do with what you will talk about in lecture or what you will be tested over. His teaching and testing style are the weirdest and worst I have ever encountered, you can definitely tell that he is a researcher and not a professor (he doesn't let you forget it either because he brings up all his published papers and awards and friends who are nobel laureates every five seconds). He's a nice guy, but definitely not used to teaching this large of a class at this level and it shows, I don't think he prepared me very well for 30A and I did not enjoy his class, if you can take someone else, I would highly recommend doing so.

Honestly, Weiss is a very enthusiastic person who genuinely enjoys going to lectures and even woke up at 4 in the morning one week to give skype lectures from abroad.

However, this class is really not the best place to learn anything that is in te course name "Chemical Energetics and Change". Towards the end of the first week, it was pretty apparent that the way that Weiss was teaching gas laws was overly simplified and not really helpful for students in doing the homework. In addition, he would occasionally interrupt the topic to start speaking about the various kinds of spectroscopies, which a lot of people found interesting, but it really took away from the time he could have spent teaching gas laws. Starting second week, I started going to Li's lectures because I felt that if I was going to learn anything this quarter about chemistry, it was not gonna be from this class.

I didn't know how bad the class was going to be though. Starting third week, we started thermochemistry while the homework followed the book and was on questions of phase equilibria. I think I gave up on trying to find what he talked about interesting when he went into semiconductors. It just was not what I felt that I wanted to or needed to learn from the course. When the unit got into thermodynamics, a lot of people were stuck on the harder problems because we had no idea whether to spend our time trying to keep up with what Weiss was teaching us, or to try to learn the concepts in the book to solve the homework problems.

Of course, the latter would have been very good for learning the topics we were supposed to in this course, but it probably would have killed my grade in this class. Even though the stuff we were supposed to be learning was gas laws and phase equilibria in the first 2 weeks, the first midterm (based on the first 2 weeks) largely tested the various types of spectroscopies. The second midterm, in turn largely tested electrochemistry and semiconductors while we were supposed to be learning thermodynamics. I don't think that the final had any material we were supposed to be learning in the course at all. The tests were all qualitative, usually involving very little math and mostly just describing how things work; really just regurgitating what he tells you.

The TA will probably be your lifeline in this course to doing homework and understanding either what the book tells you and what Weiss tells you. But that is also a lot of stuff to fit in 50 minutes so you should definitely go to office hours. Weiss's own office hours were actually pretty inconvenient for me and I didn't really like him anyways so I didn't go. But I heard that he doesn't really have anything that he could use to show students how to do problems; no whiteboard or chalkboard. So I guess the office hours are best for asking him questions on the lectures.

The class had 3 midterms, but everyone is allowed to drop one midterm. I really don't know how good that is if everyone gets curved at the end of the class though...

All in all, I really regret taking this professor, but I sat through Li's lectures and she completely skipped over acid-base equilibria. That is not to say that Weiss did it well, but rather that we understood that we had to self-teach ourselves it.

Professor Weiss cares more about student mastery of the material than any other professor I've had. Would definitely recommend to anyone who wants to truly master this courses's curriculum as well as material that was removed from the course.