"The major thing I have learned in this class has been that questions are OK without answers, that questions are the most important thing."

-workshop student

Investigative activities move one step beyond concept labs and involve students in the larger practice of scientific inquiry: problem-posing, problem-solving, and persuasion (Peterson & Jungck, 1988). Students design their own investigations in small groups and write up their results in a scientific paper. Setting up situations in which students can pose their own problems for investigation, develop methods of attacking the problem, and then persuade their peers that their conclusions are correct is more motivating and involving than being assigned instructor-generated problems, engages higher-order cognitive skills than repetition of "cookbook" exercises, and gives students a more realistic view of how science is actually conducted. Students begin to realize that the design of investigations takes more effort than obtaining results, and that scientists do not auto-matically discover the "right" answer through experimentation, but must persuade their peers that their interpretation should be accepted.

We have have tried to take advantage of our year-long sequence by developing activities which will build students' skills throughout the year. In the fall, we focus on the power and limits of scientific knowledge, and the idea that science is a persuasive activity. One investigation we use in the fall term involves DNA fingerprinting using PCR amplification of students' own DNA. The context is a crime scene, in which one student is randomly chosen as the suspect; the class must make the determination of guilty or not guilty. This experience has been very useful in helping students understand the limitations of DNA fingerprinting, the kind of information it produces, and the difference between proving someone guilty and proving them innocent; in effect, the difference between confirming and rejecting a hypothesis.

In the winter, we focus more on the actual practice of asking questions and testing hypotheses. We asked students to design an experiment investigating some aspect of homeostasis, using certain kinds of equipment (blood pressure cuffs and stethoscopes); their questions thus tended to focus on blood pressure and heart rate. These variables make excellent subjects for investigations, since they are easily manipulated and measured, and are relevant to questions of cardiovascular health, a topic of great interest among our students. Students focused on formulating an appropriate question and designing a controlled study, and we structured a number of the concept labs to include methodological considerations, in order to give students practice before they actually had to conduct their investigation. We adapted a technique (Lawson, Rissing, & Faeth, 1990) in one concept lab, on transpiration in plants, that allows students to discover for themselves the concepts of independent and dependent variables, observer bias, and experimental controls. We followed this with a critique of a sample investigation, written by the instructor, which then served as a model for their own papers. We also had students write research proposals for their investigations, on which they received feedback both from their peers and from the instructors. The organization and structure of these experiences proved to be excellent preparation for the investigations, which improved significantly over previous terms.

In the spring, we introduce the idea of modeling as a investigative method, using a variety of computer simulations including MacClade, a tool for building phylogenetic trees, and the BioQUEST publication Environmental Decision Making, which allows students to design investigations of the growth of wild populations under certain environmental pressures. We are currently developing several other population simulations.