hydrologist, are monitoring the water in Stones River. The video shows the team visiting the river and conducting various water quality tests. Students in the classroom are asked to assess the water quality at a second site on the river. They are challenged to select tools they can use to sample macroinvertebrates and test dissolved oxygen, to conduct these tests, and to interpret the data relative to previous data from the same site. Ultimately, they find that the river is polluted as a result of illegal dumping of restaurant grease. Students must then decide how to clean up the pollution.

The problem-based learning activity includes three sequential modules: macroinvertebrate sampling, dissolved oxygen testing, and pollution cleanup. The modules are preliminary to the project-based activity, in which students conduct actual water quality testing at a local river. In executing the latter, they are provided with a set of criteria by which an external agency will evaluate written reports and accompanying videotaped presentations.

The ability of students and teachers to progress through the various cycles of work and revision within each module and devise an effective solution to the larger problem depends on a variety of resource materials carefully designed to assist in the learning and assessment process (see Box 7–2). Students who use these resources and tools learn significantly more than students who go through the same instructional sequence for the same amount of time, but without the benefit of the tools and the embedded formative assessment activities. Furthermore, their performance in a related project-based learning activity is significantly enhanced (Barron et al., 1995).

Genscope™ This is an innovative computer-based program designed to help students learn key concepts of genetics and develop scientific reasoning skills (see Hickey, Kindfield, and Horwitz, 1999; Horwitz, 1998). The program includes curriculum, instructional components, and assessments. The centerpiece is an open-ended software tool that permits students to manipulate models of genetic information at multiple levels, including cells, family trees, and whole populations. Using GenScope™, students can create and vary the biological traits of an imaginary species of dragons—for example, by altering a gene that codes for the dragon’s color and exploring how this alteration affects generations of offspring and the survivability of a population.

The developers of GenScope™ have pursued various approaches to the assessment of student learning outcomes. To compare the performance of ninth graders who used this program and those in more traditional classrooms, the researchers administered a paper-and-pencil test. They concluded that many GenScope™ students were not developing higher-order reasoning skills as intended. They also found that some classrooms that used these curriculum materials did not complete the computerized activities because of various logistical problems; nevertheless, the students in these classrooms

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