Despite the limitations of traditional lectures, many institutions are forced to offer high-enrollment introductory science courses. Many professors who teach these courses feel that lecturing is their only option, and can only dream of what they could accomplish in smaller classes. However, there is a small but growing group of science faculty members who have developed ways to engage students in the process of thinking, questioning, and problem solving despite the large class size. Strategies in use in introductory courses in biology and geology are described in the sidebars.
Although many of the methods described in these sidebars are consistent with what experts know about how students learn (see Chapter 3), they may not be welcomed by all of the students in a class. There are several ways to help students make the transition from passive listeners to active participants in their own learning (Orzechowksi, 1995):
Start off slowly; students may not have much experience in active learning.
Introduce change at the beginning of a course, rather than midway through.
Avoid giving students the impression that you are "experimenting" with them.
Biochemistry, Genetics, and Molecular Biology at Stanford University
Professor: Sharon Long
Enrollment: 400 students
One important tool I use to engage students is to create opportunities for thought and for active pursuit of an unknown during the class session. If I give a lecture for which I provide notes-a common practice-I always leave blanks in critical parts of the notes. On the board or transparency, I indicate the unknown. I pause while I talk about it, drawing the students' attention to the hole in the notes. If possible, I ask for suggested answers or for a vote among the possibilities. By arranging the pause in your lecture you can give the students the chance to puzzle out the question themselves and to preview their ability to work on the questions independently. And only by attending class can a student gain all the information-an important draw to encourage class attendance.
In teaching formal genetics, I draw out a genetic cross first in general form (in this example, a Drosophila eye color inheritance test):
w+y x w w
Then I put into the lecture notes-a completely blank Punnett square to show the structure of the approach-but not to provide the answer.
The students encounter this as an unknown, because I address the contents of each line, and each box, as a question. (Everybody, consult with your neighbor for a minute-now second row, anybody tell me, what should be in these two blanks at the top? What would be the genotype and phenotype for the bottom right box?)