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The school curriculum can become a topic of heated public debate. Last year, for example, the Kansas Board of Education removed any direct reference to the word “evolution” from the state’s science standards.

But the turmoil over a standards item raises a broader question: How do students best learn science? The science that many of us learned in school was “ready made.” Textbooks were full of hindsights of scientific research, but they provided little sense of why or how the research was conducted.

By contrast, WCER researcher and classroom teacher Susan Johnson sees her classroom as an opportunity for students to experience "science in the making." Johnson teaches at Monona Grove (Wisconsin) High School and is a researcher in WCER’s National Center for Improving Student Learning and Achievement in mathematics and science. Students in Johnson’s high school genetics course work in research groups to pose and solve problems, build explanatory models for phenomena, revise those models to explain anomalies, and defend and critique those models.

Students develop their understanding of genetics by building explanatory models for modes of inheritance (such as recessive or dominant) and revising those models to explain new, unfamiliar modes.

Students do what scientists do

Students in Johnson’s class begin by studying Gregor Mendel's basic model of inheritance. They read Mendel's explanation of the simple dominance mode of inheritance. Mendel “himself” (often played by a graduate student) visits the class to help them recreate his model. With Mendel, they look at the flower structure of the pea plants he used in his famous experiments. Together they count and classify peas previously gathered from three generations of plants to see how different traits, such as color or shape of seed, pass from one generation to another.

Student research groups are then provided, via a computer simulation, with random collections of hypothetical organisms that follow the simple dominance model. Over several days the students become more familiar with the model by producing generations of organisms from the random collections. They determine which variation of a particular trait is dominant and which recessive. They match genotypes (genetic makeup) to phenotypes (appearance), and they explain and predict the types of offspring possible from any two-parent organisms.

Over the next few weeks the collections of organisms (generated by the computer) exhibit anomalous data that are the result of modes of inheritance other than simple dominance. Because the students have no models that explain these data, they must revise Mendel's model to explain the anomalies. However students do not go to text or teacher for the answer. In this effect-to-cause problem solving, similar to that done by classical geneticists, the problems are open-ended. There is no one-and-only-one solution, because multiple models can be proposed and defended.

“In this process students become invested in what they do,” Johnson says. “They feel an ownership of ideas, which, as seen from their excitement, was a very powerful motivator. They also develop a deeper understanding of genetics, because they develop their own models rather than solely memorizing something presented to them already in final form.”

Teams learn to persuade

Students also experience the important scientific activity of persuasion. First, they persuade themselves about the adequacy of a particular model. Then they persuade others within their research group. They share their models at classroom conferences.

“It’s a very powerful moment when a student model is successfully used to predict the results of a particular cross,” Johnson says. “Watching students defend their models and explain their thinking is convincing evidence that we generally underestimate the contribution students can make to their own learning, and to that of their classmates.”

Students also prepare scientific posters that document the groups’ methods, the data they used, and a model they developed. The poster session is attended by peers, parents, teachers, and administrators. “The student groups are even more impressed with what they have accomplished when they describe their models to others outside the classroom and use those models to explain various human traits, “ Johnson says.

Research shapes practice

A decade ago, Johnson decided she wanted to update her knowledge; she entered a master’s degree program in science education with an emphasis in genetics. “The courses in genetics were fascinating,” she says. “But the courses in education had the greatest effect on me. Now my classroom is a very different place.”

Over the past few years, four dissertations have been written at UW-Madison on the model-revising process that Johnson’s students use and on the relationship between students’ problem solving and their use of models. Johnson says the effects of those studies on her course include more emphasis on persuasion through the writing of research papers and explicit discussion of problem-solving strategies.

Rather than acting primarily as a disseminator of information, Johnson acts as a laboratory director, giving encouragement when it is needed and asking the student researchers: “What anomalies have you encountered? How does your proposed model explain this cross? What strategies have you used to test your model?”

She finds the new role refreshing but challenging. “In the past, when students were working on a problem, it was typically a matter of helping them figure out what equations to use to arrive at the expected answer,” Johnson says. “As valuable as that might be in some cases, I found that helping students develop strategies for producing tentative models, judging the adequacy of those models, and dealing with anomalies that arise in the problem solving process are far more valuable in a science classroom devoted to having students do and understand science.”

Could more teachers teach this way if they wanted to? Johnson says,“It’s a different way of thinking about the teacher’s role in the classroom, but most teachers could adapt, especially if they could have some experience with this new role.Those who like a very structured and predictable classroom might feel a little less comfortable.”

At times, this teaching strategy means watching students wrestle in frustration—for example, with a model that explains all but one of the crosses that they have performed. “A few students who have been successful in the more traditional classroom find it unsettling,” Johnson says. “But it also means seeing their eyes light up when a tentative model that they have proposed explains all the crosses they have performed, including that difficult cross.” In this case, it’s not just the "I get it!" moment, which results from assimilation and practice, but also the "We did it!" moment, when they use the knowledge they constructed to solve a difficult problem.

Johnson’s course was developed in collaboration with her peers in WCER’s National Center for Improving Student Learning and Achievement in mathematics and science. Funding for her research was provided by the Office of Educational Research and Improvement, U.S. Department of Education. Other research that informs her work was conducted and published by James Stewart, Thomas Carpenter, Elizabeth Fennema, Angelo Collins, Richard Lehrer, Thomas Romberg, Leona Schauble, Bruno Latour, and others.

For more information see the NCISLA web site at http://www.wcer.wisc.edu/NCISLA or contact Johnson at skjohnso@facstaff.wisc.edu.