Oral Exams in Physical Chemistry

Contributed by Darin J. Ulness, Concordia College

Details:

In physical chemistry the oral exam is part of a two component exam along with a written take-home. For the first exam the oral part is worth only 15% of the exam total. For the second and third exams the oral is worth 25% and 30% respectively. All oral components are worth 30% for physical chemistry II.
In all cases the exams are intended to last about 30 minutes. Most of the exams are given during the lab period, but overflow into non-scheduled class time can occur in physical chemistry I. The largest class so far is 26 students in which the oral exams were conducted over 2-3 days. This got to be rather demanding and draining and was probably near the limit that I would be able to handle effectively.
I generally do not supply a list of potential questions before the exams, but I do supply a list of the types of questions to expect. Furthermore, TAs run practice oral exams to individuals or groups before the first exam. Over half of the students take advantages of this practice session. For each exam, I have a set list of two or three questions that I ask everyone. These questions lead off each general topic area I want to cover in the test, but I let their answers guide course of the exam. Each general category is graded with a percentage right after the exam. I go over the grades with the students at the end of the exam and they have a chance to contest their grade. Generally it is clear to student what they know and what they don't know. Grades are generally high. For the group of students I work with, grades aren't the primary motivator when it comes the the exam. Doing well and not embarrassing themselves is the strongest motivator.

Goals and assessment of the Exam:

The goals of the oral exams are to

provide an unambiguous testing environment. It is easy to make sure the students know what is being asked. There is no way to misinterpret the question since I am right there talking with the student.
serve as a testing tool for concepts. Physical chemistry is a mixture of heavy mathematical computation based problems and conceptual problems. The oral exam provides a good environment to probe the students understanding of the conceptual side of the course material.
expose lack of understanding to students. Just as the questions to the students are unambiguous, their responses are as well.
serve as a teaching tool. Often the concepts from the oral exam stick with the students since their misconceptions are exposed in a higher stress situation.
give the students practice for presenting complicated ideas. Being able to present material orally to someone often requires the most sophisticated level of understanding.
give good practice for grad/med school oral exams, interviews and presentations.

The above goals are unfortunately difficult to assess effectiveness quantitatively. This is primarily because there is a small data pool and no control group. A qualitative assessment comes from student course evaluations. Below are some comments that address the above goals.

“Even though I stress out about the oral tests, I think they are a fair way of evaluating my knowledge.”
“The oral exams are the most useful because he shows you what you do know and do not know”
“I like the oral exams because I feel like I have a better understanding of the material after I’m done”
“Oral exams help students prepare for the exams and is good practice at communicating complex ideas to others”

What to Expect

The students will be nervous! Students show nervousness in a variety of ways. Some become hyper while others slow down their speech. Students answer questions in a variety of ways as well. Some give very short terse answers which will need addition probing on your part. Others give a "core dump" of their knowledge on the topics, sometimes answers a different question then what is being asked.

Strategy and Tips

Here are some tips that I have found useful.

Allow enough time. Do not underestimate how long the exam might take. It is amazing how little one can ask in a half-hour.
Do not be afraid of very quick exams. Some students complete the exam very quickly relative to others.
Listen! This is hard, especially when you have many exams to do. During normal conversation we all let are attention wax and wane. You shouldn't do that here. It is unprofessional to have to ask the student to repeat an answer because you were not paying attention.
Have a poker face, but do not be completely without response. During normal conversation we all pick up on body language so by hiding this you throw-off the student. I try to pretend that I am listening to a colleague telling me something.
Provide minimal help. If you help too much you invalidate the exam.
Work to the student’s strengths. Try to talk in the language that the particular student uses. If they like to think about a concept in a different way
Be gentle and supportive.
Have your questions prepared ahead of time.
Keep note taking to a minimum during the exam. It is unsettling to the student if it looks like you are evaluating every word they say.
Grade high. The situation is plenty stressful to demand a strong effort by the students. Grades should not be the primary motivating factor
Do not do an oral version of a written exam.
Look to ask primarily conceptual questions.
Try to come up with questions that can lead you through the exam.
Focus on important or main points.
Avoid gross inconsistency, but welcome minor inconsistency. In order for everyone to have a similar exam one exam should not deviate to much from another. But there should be some individuality to each exam. This is one of the advantages of the oral test.