Lab grades are based on quizzes, written work, and lab technique. The weight or percentage of each of these grade factors varies from course to course and semester to semester:
| scores on prelab and comprehensive final quizzes | 35-40% |
| lab notebooks, worksheets, written reports | 35-45% |
| performances in the laboratory - "technique" | 25-35% |
Missed labs can easily and quickly bring down your lab grade. To prevent being docked if you have to miss a lab, see the missed lab page.
For answers to frequently asked questions, including grading issues and problems with your TA, see the FAQs page.
Almost every experiment has a "prelab" quiz. The policy of prelab quizzes was begun years ago in the organic chem teaching labs, in response to the observation that students would walk in the door to begin a lab and they had not yet even read the lab! Thus, the prelab quizzes were designed to make sure that the students did the reading.
Each lab quiz is worth 10 points. Since each experiment is worth 25 points, it is important that you do well on the prelab quizzes to get a good grade in the course. The final quizzes are worth about 40-45 points, depending on the lab course.
Prelab quizzes do not require that you grasp difficult concepts. They cover the assigned reading in the Lab Manual, both the background/theory section and the procedure section. One of the study questions is likely to be on the quiz. The important physical properties (is the reactant a liquid or a solid?) and hazards (are the solvents you will be using toxic?) are fair quiz game.
The prelab quizzes are written and maintained by the Lab Coordinator. This is so that they will be consistent from section to section and TA to TA. The quizzes are not designed to "trick" you, and if you ever feel that a particular question is simply a "trivia" question, please discuss the question with the Coordinator.
Practice prelab quizzes are available on the orgchem website:
The comprehensive final quizzes are designed to test your grasp of organic lab techniques. How much solvent is needed to recrystallize a solid, and should that solvent be hot or cold? In an extraction, which solvent is on the top/bottom, and how can you predict this? In chromatography, will a polar compound move faster or slower than a non-polar compound? If you have been paying attention the entire semester, you should know the answers to these questions without studying for the final quiz. A good way to study is to review the online prelab quizzes. Review sheets are available on this site:
Written assignments include: molecular model exercises, spectroscopy problems, and the CAS assignment (majors only). The point values of these are assigned to correlate with how many lab periods they cover, using the rule-of-thumb of 25 pts/lab meeting. Written reports are required for only a few experiments, and only in majors and/or organic chem 2 lab courses. The directions for these will be given in lab.
Lab reports consist of a prelab, data and observations, and write-up. They are worth 10 pts, out of a total of 25 pts for each experiment. We do not want students to spend a lot of time writing long lab reports. Be clear, be consise. You will not impress your TA by copying pages from the Manual or Text; you will impress your TA if they can easily read and understand what you write. Your TA wants to know if you understand the scientific process:
You must think about what happened in lab and make conclusions on what you saw, and not what the book says. The conclusion should be only a few sentences long.
The prelab is worth 4 pts, the data/observations 2 pt, and the conclusion 4 pts. The prelab is due as you walk into the lab, the rest is due either as you leave or a day or two after you complete the lab. Exact due dates are at the discretion of the TA. Each TA has the right to set and enforce their own policy on late lab reports.
Note: the study questions are not to be handed in. Instead, they are designed to lead you to a better understanding of key concepts. If you do not understand a question, go to the office hours or email your TA. The study questions are fair game for prelab quizzes.
The "technique" grade is basically an "attendance" grade. Attendance in this case means not simply physical presence, but whether or not you are paying attention to what you are doing. The TA evaluates how well each student:
You can ask your TA how to do a new procedure and not be penalized by losing technique pts. You are here to learn to do organic chemistry lab techniques, and you cannot do this if you do not ask questions. You may remember most of the things to set up from your reading, but it is expected that you will not remember everything. But, if you continually forget to clamp down glassware and it breaks, you are using bad technique. If you are told to run an IR and go stand in front of the GCs, you aren't paying attention. If you connect your steam line to your condenser, you are not using the equipment properly. If you take off your goggles, you are not following safety rules. If you constantly ask your TA what to do next, you are not able to perform the experiments.
The technique grade is assigned by your TA. It may or may not be assigned each lab meeting; your TA may keep simple plus and minus notes in their grade record. Technique grade cannot be assigned on the basis of your lab report, it must be assigned according to visual observations of each student in lab. Yes, it is subjective. You may be doing stellar work most of the time and your TA does not see you until you drop your flask. Or, your TA may simply like you or not like you (TAs are human too), and you may feel that this affects your technique grade. You can ask your TA why points are taken off and they should have a reason. If you feel that your are being unfairly graded, see the Coordinator.
In all honesty, the technique grade assigned by TAs is not the determining factor in your lab grade. The technique portion of the grade varies very little from student to student. The point guidelines set by the Coordinator are this:
In our experience, most students are competent enough in lab, and leave the lab session with a 4 pt technique grade.
But, the technique grade is worth 5 pts!! Ah. Well, here's the reason below, in the form of my (Coordinator) response to an email from a student concerned about their technique grade:
| "My TA has said that we will rarely if ever get full points for the technique grade. This concerns me greatly. I have put a lot of time and effort into this class and no matter how much I do I cannot get more than 4/5. Do you have any suggestions? Is this true for all of the lab sections also?" My answer: It's true for all lab sections, and it's my fault. I advise the TAs to give a 4 to each student, like an "attendance grade", as they walk in the door. Usually no one gets a technique score of other than 4 for a lab. In other words. 4 is a "perfect" score. Why, you ask? Okay, say I arbitrarily set the technique score as "5" out of 5. Then, at the end of the semester the average grade in each section would probably be 95% of the possible points. Students in this country are trained to think that 90% and above is an "A". Well, the university would frown upon us if we gave each student an "A". And you know as well as I do that everyone does not do equally well. A section of students divides naturally into A and B and C students. So, would you rather get 94% of the possible points and get a B? If so, I will change my grading advice to the TAs. In all reality, from observing lab grades over the last 10 years, it's the quizzes that determine the lab grade. Notebooks are 10 points out of 25, most students get the same score within a point or two. Technique grades are almost always 4, with an occasional 3 or 5. If you do something outstanding, like isolate beautiful crystals and run to show them to me, or finish in half the time with excellent results, always have your equipment properly clamped, or clean up the balance room without being asked, and know where the wastes go, well, you may gain a technique point. |
