In this interpretivist case study, four professors who have effectively used clickers to teach chemistry at a large university in a western state were observed and interviewed. Seventeen 50-minute class periods were observed and four 40-50 minute interviews were conducted. Having an institutional culture that promotes the use of clickers and standardizes technology across classes has made professors more likely to use them in their classes and has made their implementation easier for the professors who do use them. The importance of clickers as a means of increasing student interaction appears to be greater in larger classrooms. However, interaction in extremely large classes may not be effective, even with clickers. Clickers seem to have increased student attendance. The professors described multiple ways of using clickers to teach a chemistry course effectively, some "natural implementations", some more deliberate, but rejected the idea of forced implementation. (Contains 2 tables.)