Submitted by Amanda Reig / Ursinus College on Mon, 01/05/2015 - 11:37

So I've come to realize that my least favorite thing about teaching inorganic chemistry is grading their homework assignments.  I typically have about 15 students and in the past I have assigned weekly graded problem sets.  They are allowed to work together on the homework, but must hand in individual papers.  I get bogged down in the somewhat mindless repetitive task of grading their assignments.  That said, I do tend to try and challenge students through homework and it has typically been a reasonable chunk of their grade in this class (20%) which helps to balance the difficult exams.  How do you all handle homework in Inorganic?  Ideas I've thought of are listed below and I'd like to hear your thoughts on different approaches.

1) Continue assigning and grading the HW assignments as usual

2) Continue assigning weekly fraded homework but having a student grader

3) Give students "suggested" problems but do not collect anything for grading (but post answer keys)

4) Assign problems and then grade only selected problems

5) Assign problems and grade on a simple check plus/check/check minus system

Anne Bentley / Lewis & Clark College

I used to assign long problem sets (8-10 big problems) every two weeks, and my students and I both disliked that system.  Then I adpoted a system from a pchem colleague in which I assign one problem due at the beginning of class every single day. 

I think a class of 15 is about as big as I would go with this system.  I try to grade the problems and return them to the students' department mailboxes within 24 hours. They either receive full credit (10 points) or they get a "re-do", meaning they get one more week to work on the problem.  After a week, they get a final grade out of 10 points. I allow them to drop one problem score, and most years we end up with 20-25 total problems.  (I think the homework is worth 20-25% of their overall grade, and most students do very well.)

I also create a list of recommended problems per chapter with solutions, but it's up to the students to study those independently.  I emphasize that the one-problem-per-day system cannot cover everything and that they really do need to complete all the extra problems, too.

Students have been very positive about the system, and I really like it, too. I can talk about the problems in class, and it really keeps everyone up to speed.  It allows me to see who is falling behind, and it keeps them from ignoring the class entirely.

Of course the most effort is required the first year of this system, and I do update/adjust problems every year. 

Good luck!

Tue, 01/06/2015 - 10:42 Permalink
Chip Nataro / Lafayette College

I do problem sets about every 2 weeks. In total 8 per semester and 2 per exam. On the day they are due, I have some students come in early and write up their answers on the board. We then discuss their answers and any other solutions that other students may have come up with. Students are allowed to take notes on their problem sets but it must be in a different color. Grading is then based on if the student appears to have put forth a reasonable effort in answering the question. Essentially they get full credit unless their originial answer is blank or is completely off base. I read over their answers and notes and will comment if it looks like they missed something important. So, I wouldn't say grading takes me a long time and generally the averages are high. But we have exams to make sure things don't get out of control.

Mon, 01/12/2015 - 12:15 Permalink
Barbara Reisner / James Madison University

I too used to assign long problem sets (about 10 problem sets). When my class size got above 30 I had students work in teams. Now that I have over 50, I've had to move to using online homework (Sapling). I also recommend problems from the book; the solutions are available for free, online from the publisher. The level of the online homework and book problems isn't quite at the level where I'd like my students to be. However, its a good way to check if they have the basics. (I make my online homework due 24 hours after class to keep the students honest about keeping up.)

Because I think working challenging problems is important, I've created a daily problem for class each day. (Usually the problems have multiple parts.) The students work in teams of three to solve the problem. They turn it in for credit/no credit and we spend some time talking about it in class (when they're struglling) or during the next class (if I find that there is a problem that students consistently have). I like this system because it allows me to see what the students are thinking on a real time basis. It doesn't take long to grade because most of the discussion about problems happens in class. 

Like Anne, I have to remind the students that there are other problems that they should be able to do  (hence the book problem assignments and the online homework). It's not perfect, but it's made grading homework in supersized inorganic more managable and more an exercise in understanding the students' thought processes rather than grading.

Mon, 01/12/2015 - 16:36 Permalink
Chris Hamaker / Illinois State University

I've generally done number 1, although usually only 8 or 9 in a 15 week term. Previously, when Illinois State had only one semester of inorganic chemistry, I would do #3 for descriptive chemistry (assign 20 - 25 problems) and would ask 2 or 3 of them on the last hour exam, and they did very poorly. I asked some students, and they didn't do the problems since they weren't graded and only a few of them even looked at the answer key I posted on the bulletin board. 

Last semester, my first teaching the new "Advanced Inorganic Chemistry" (our second Inorganic course in the major, recently added), I tried Sapling for online homework. It did not work at all. There were very few advanced inorganic problems available and I had difficulty finding problems to assign about 5 weeks in.

I have done #5 in the past, but I have found that that model of grading often led to students doing the minimum work possible. I'm teaching Advanced Inorganic again this spring, and will go back to good ole #1.


Thu, 01/22/2015 - 10:52 Permalink
Amanda Reig / Ursinus College

Just wanted to post a quick follow-up.  After talking a bit more with Anne about her system, I've been trying it out this semester and I actually really like it.  For the most part, I think the students do also.  It keeps them on top of the material and allows me (and them) to catch on quickly when something isn't clicking.  I had one particular question that most of the class did not understand and it allowed me the following class period to give them some additional information and direction and then send them back to try again (at which point 95% got the problem correct).  

Because the students have the chance to re-do the problems they miss, I find they actually spend more time figuring out what they did wrong and why than they typically did with a more traditional problem set approach.  I did arrange it so that the students get full credit if they get the problem(s) right on the first try, and up to a maximum of 90% credit on the re-do.  This encourages them to get it right the first time, but doesn't punish them much for needing a second chance.  I could probably make some of the problems a bit harder, but it has definitely be working to gauge their understanding of the major concepts.

Finally, I can usually get through a stack of problems in 10-20 minutes (I have 15 students enrolled currently) since it is an easy right/wrong system.  I no longer dread the grading process like I used to so that is a definite win.

Wed, 02/18/2015 - 22:49 Permalink