QUESTION: In the chemical reaction written above, which is the reducing agent and which is the oxidizing agent? Choose from answers A to E, listed below.
Upon first thought, you might not think that students would be super excited to start off their Chem 31B lecture this way. But as I look around the lecture hall, I see students with their heads together trying to figure out the correct answer. Some are thinking hard, trying to remember the last lecture. Though a few don't seem to care too much, the majority of students are very much involved. Right from the get-go, these students are engaged in the class material.
After a brief time, the students submit their responses via electronic handheld clickers and the instructor, Dr. Jen Schwartz, displays the class results on the projector screen. There is understandable excitement from students who got the correct answer. To my surprise, the students near me don't seem to be too upset if they got it wrong. They take it in stride as part of participating in the lecture, as a way of making the material stick.
I attended Dr. Schwartz’s lecture to see how clickers can be used to facilitate learning in a large lecture class. I was impressed with how she used the questions to get the students actively thinking about the material. This was very different from a traditional Intro Chem lecture, where students sit passively and (hopefully) absorb the material presented.
Clickers (or Classroom Response Systems [CRSs] or Personal Response Systems [PRSs] if you want to get technical) are increasingly becoming adopted in large lecture science classes. Typically, several clicker questions are asked during the lecture period, and the instructor monitors the student responses (in aggregate) in real time. There is a wide variety of question categories that can be asked to ascertain a range from "I am in class" to "I can apply what you just told me."
Clickers can help you:
- Review material from the last lecture. To facilitate student learning in the current lecture, it helps to "prime the pump” with clicker questions about what you covered last time.
- Hold students accountable for reading. Encouraging students to do the reading can be difficult in any class, but may be especially so in the sciences, where students commonly expect that the material will just be covered in class anyway. Clicker questions make the students accountable for coming to class prepared.
- Identify student misconceptions. The expert blind spot can be a big challenge to effective teaching, and so it’s incredibly valuable to have a real-time handle on student misconceptions. Student responses to clicker questions can pinpoint what they don’t understand. You can even ask students at end of the class to identify the muddiest point from the day's lecture.
- Help students avoid/overcome misconceptions. When you find a misconception shared by many students, you can deal with that directly by spending more time on the topic in the lecture. Ask follow-up clicker questions in subsequent lectures to check that the students have straightened out the problem.
Disadvantages to using clickers:
- You are pretty much limited to multiple choice or true/false type questions. There is a lot that can be done with those styles of questions, but it is a limitation.
- Technology issues. If the clicker responses aren't being received properly or there is a connectivity problem in the middle of the lecture, you might spend valuable time getting the system up again. Testing before each class period is probably a must.
- Price. There is an upfront price tag to get the appropriate equipment. The Stanford Bookstore sells individual clickers for about $52 each to students.
- To test them before buying, you can check out a set of clickers from the Center for Teaching and Learning on campus.
- There are also "low-tech" alternatives—cue cards and student thumbs (up/down), which capture some of the essential elements of the system, although they have disadvantages as well.
- The experience is only as good as the question, as Dr. Jen Schwartz emphasizes. If you ask a bad question, or one that is poorly worded, it won’t help to the learning process. Worse, you might end up with some angry students on your hands. Examples of good clicker questions for general and organic chemistry are these from Herzfeld (Brandeis) and Wamser (Portland State).
- You probably won't be able to cover as much material in each class period. On the flip side, the students hopefully will have a much richer understanding of what you do cover. It may be well worth sacrificing broader superficial knowledge for more focused but deeper understanding.
Overall, there are a number of reasons why using clicker questions in a large lecture class makes sense. When used effectively, clickers can help the students become actively engaged in the lecture and help them learn the material better. Click it to stick it!
Bob Rawle is a doctoral candidate in Chemistry at Stanford.