Understanding Koch's postulates, including how they are used to study the spread of disease within a population, is central to the teaching of microbiology. These concepts are often presented and discussed with little or no historical background, and as a result students fail to appreciate how the field has developed from past to present. We designed a lesson based on the story of Typhoid Mary to engage students in the learning and application of Koch's postulates in the field of epidemiology and provide insight into the interplay between scientists and the public as illustrated by this episode. The lesson uses an interrupted story technique in which students watch a documentary about Typhoid Mary, with pauses to discuss the events and engage in a role-play to reenact Mary's trial. The purpose is to improve student understanding of central concepts and to foster a deeper understanding of issues associated with the nature of science (NOS), such as how the process of science is influenced by culture and society (and vice versa). This lesson plan was created for a college-level microbiology course for non-majors, but can be easily modified for use in high school settings.
DNA is a central topic in biology courses because it is crucial to an understanding of modern genetics. Many instructors introduce the topic by means of a sanitized retelling of the history of the discovery of the structure of DNA by James Watson and Francis Crick. Historical research since 1968 has revealed that Rosalind Franklin's contributions were more significant than they are usually depicted. In light of this, we developed a two-class lesson plan that draws attention to Rosalind Franklin's role in the discovery and to the social and cultural aspects of science. The first class provides background information regarding what led scientists to recognize that DNA was the molecule of heredity. Students watch a documentary video that includes interviews with some of the surviving protagonists. Students (working in groups) are then asked to debate Franklin's role to refine their awareness of how social and cultural factors affected both the process of science and how it has been recounted. The second class has students work in groups to build a structural model of DNA through hands-on activities. The essay concludes by drawing attention to how the two-day lesson plan, developed for a college-level biology course, can be adapted for use in other settings.