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Working on Problem Sets

Getting Into the Right Mindset

You've probably handed in lots of problems during your high school years. However, it's very likely the expectations for the problem sets in this course are much different that what you're used to. Read through these questions and answers to be sure you have the right mindset before starting work on the problem sets.

1.  What's the point?

Problem sets are assigned to give you an opportunity to tackle challenging problems in light of the material we have covered in lecture.  Can you take the ideas that have been covered and apply them to new situations?  Can you logically combine different ideas to solve more intricate problems?  Do you really understand the ideas that have been presented so far?  

Problem sets are not meant to be an evaluation of what you know; instead, they are an opportunity for you to deepen your understanding and develop your logical reasoning abilities.  I expect you to get help from me when working on these, and I'm happy to provide it!  There is no excuse for getting a low problem set score.

2.  My focus should be on getting the correct answer, right?

Wrong.  Your focus should be on a clear, thorough understanding of the problem, the logical thought process used to solve it, and a coherent, succinct presentation of your solution.  The paper you turn in should demonstrate that you have accomplished these goals.  I will glance at your final answer, but only after I've looked for the above.  It's very possible to have the correct answer and get little or no credit for it.

3.  What are you looking for when you grade problem sets?

I'm looking for evidence of a clear, thorough understanding of the problem, the logical thought process you used to solve it, and a coherent, succinct presentation of your solution.  

Don't try and fake it: it's usually clear when someone really knows what they're saying as opposed to someone who's throwing around technical jargon they don't truly understand.  In fact, you should try to avoid technical terms wherever possible, unless it seems necessary to avoid confusion.  Everything we do boils down to simple ideas that you could explain to your mom.  (You should be able to explain it to your mom, and you know she won't put up with undefined jargon.)

4.  How much should I write down for explanations?

Just enough to have a clear, complete explanation.  More is generally not better, especially if you consider that when folks ramble on for sentence after sentence, they usually end up contradicting themselves somewhere; that flushes your logic every time.  Instead, ask yourself if your presentation (using words or equations) has any logical holes, and fill them.  See my problem set solutions for examples.

5.  Do I need to explain operations that are purely mathematical?

No.  There's never any need to write something like, "Now convert from J to kJ," or, "Now plug in the variables." If they're not given, you should explain where the values of the variables are coming from, but if you're just doing basic algebra, I don't want a play-by-play.  If it feels like a waste of your time to write it down, it probably is.

6.  When should I start working on the problems?

As soon as we cover the relevant material, but after you've studied the ideas and correctly solved the assigned problems from each lecture.  The problems given on the sets are generally not the type that you can just sit down and complete without giving yourself time for serious thought.  

The problem sets are all but worthless if you wait until the day before to do them: it'll waste your time because you're not really gaining anything from the exercise, and it'll waste my time because now I have to wade through what usually turns out to be nonsensical gibberish, try to set aside my irritation, and give it a fair score.  (That doesn't exactly give me a good impression of you or your abilities, and I do make note of it in case you ask me for a letter of recommendation somewhere down the line.)

7.  Can I work with a group or a tutor to solve a problem?

You can certainly work with a group, but be sure to write up your final paper on your own.  That will help to ensure your work is really your own.  Otherwise, if a group writes up a problem together, it's relatively easy (but not excusable) to turn in a solution that is nearly identical to someone else's.  Obviously, that's not acceptable and I do keep an eye out for it.
If you work with a tutor, keep in mind they may not understand the point of the problem sets.  (They may think that the answer to question #2 on this sheet is 'yes,' but you know better.) The tutors will be happy to help clarify a chemical idea, but make sure you're using that knowledge to solve the problem in light of the expectations outlined here.  If (when?) you need help, I recommend you come and see me first... that's what I get paid for.

8.  When I come in for help, what should I expect?

Again, the point of all this is to give you an opportunity to develop intellectually.  Therefore, when you come in, I'll help you identify the questions you should be asking yourself in order to solve the problem, and give you some suggestions on how you can find the answers yourself.  If you get stuck again, come back: I neither bark nor bite, but I also don't want to take away the opportunity these problems present for your academic development.

9.  Should I be concerned about the overall presentation of my paper?

Absolutely.  Again, these are typically not the kind of problems where you happily write up a nice, coherent solution at one sitting.  Oftentimes you'll have no idea how to go about solving the problem, so you start by calculating things you can calculate, without any specific plan for going further.  Having done that, you may then start to see a way forward through the mire.  When you've finally found a solution, you should get out a fresh sheet of paper and write it up in hindsight.  In other words, write it up as though you saw clearly how to get from point A to point B from the very beginning, without the wrong turns and false leads.  That will help you to understand the problem and its solution on a much deeper level.  

In addition, the overall presentation says a lot about you and your willingness to seriously and contentiously engage a (possibly unpleasant*) task.  Some important things to pay attention to: Write neatly.  If you can't—be honest with yourself here—type up your sets using a word processing program with an equation editor.  (If you don't know how to use an equation editor, I'll be happy to show you.)  Do not fold the top left corner of your papers together; if you don't have a stapler, simply initial each page of your set and I'll staple it for you.

10.  Should I use the internet as a resource?

No.  The internet, like a car, can be a very useful tool.  But if you're supposed to do a 10 mile run for cross country practice and your friend drives you the last nine miles... well, you get the idea.

Again, the problem sets are meant to push you intellectually; that goal is completely undermined if you let someone else do your thinking for you.  The problem sets will always give you all the information you need to solve the problem yourself.

In addition, you certainly know that you can't believe everything you find on the internet.  What you find may be misleading or just plain wrong.

Finally, and most importantly, you are forfeiting the opportunity to formulate and ask a question of a fellow person.  You will find that you learn a tremendous amount (and sometimes will even answer your own question) when you sit down and think about how you're going to ask someone—not a machine—a question.  ``What do I know already?'', ``What piece am I missing?'', etc.  We are persons; our purpose is to encounter other persons.  Yes, that can happen through books and the internet, but when you have the opportunity for a more personal engagement you would be wise to take advantage of it.

*I'm not saying the problems sets are or necessarily must be unpleasant (in fact, some folks really like them); I'm simply acknowledging the fact that not everyone likes chemistry, and problem sets may not be your favorite pastime. I know I didn't exactly like quarter-mile sprint intervals in track practice, but they sure got me into shape as long as I was willing to push myself a little bit.

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