Have you ever taught a class that just never seemed to come together? Or one in which the students all worked together really well? Do you think that classes have their own personalities?

I first learned about the concept of class chemistry as a student teacher. My master teacher, a wonderful woman named Martha Bean, commented on one of the classes that I was helping with: “They haven’t quite gelled yet,” she said. By which she meant that they hadn’t yet gotten to the point where they could work well together and open up to each other.

Now this was in the context of an intensive English language program in Los Angeles. We were about two weeks into the new term. We saw our twenty-year old students every day for about an hour. Martha knew that, with a little time and a little direction on the part of the teacher, that the students in the class would find their way. And eventually, they did. But that isn’t always the case.

And I’m still not sure about the mystery of class chemistry. Ten years later I was in my final term of teaching in that same intensive English program. I thought of myself as a pretty experienced teacher by then. I was teaching four different groups of students. One of them had the best “chemistry” of any class I’ve ever taught. There were fifteen students who spoke fifteen different languages. They encouraged each other. They spoke only English in class. They did their homework. They were cheerful and helpful to me and to each other. At the same time, I was teaching another group of students. This was certainly one of the worst classes I ever had. The students were uncooperative, didn’t want to speak English in class, and interacted with each other only when forced to do so.

Of course, I was the same teacher, wasn’t I? To this day, I’m not sure exactly how I might have behaved differently with the two groups. Did I cause that difference in chemistry? I don’t think so. And what if I had been observed teaching one class or the other? I think that the observer would have come to very different conclusions about my effectiveness as a teacher depending on which class they saw.

What experiences have you had with class chemistry? Have you found that certain behaviors on your part improve the way the students interact? Please share your ideas in the comments section below or join the conversation on the TESOL Blog.