Improving Students' Perceptions of Benefits of Science Demonstrations and Content Mastery in a Large-Enrollment Chemistry Lecture Demonstration Course for Nonscience Majors

Article excerpt

A large enrollment, instructor-centered chemistry course taught with science demonstrations was transformed into one that was more student-centered. Course survey and examination results revealed more positive perceptions of the benefits of demonstrations and greater content mastery for students in the modified course than for those in the traditional course.

Science instructors commonly strive to make their introductory science courses more interesting, to promote content mastery, and to make them relevant to students' lives. In this article, we'd like to share how we transformed a large enrollment, instructor-centered traditional lecture demonstration chemistry course using a series of science demonstrations into one that promotes greater content mastery and is more engaging for students (using the same series of science demonstrations).

The use of demonstrations for the teaching of science is widely viewed as beneficial (Ogborn et al. 1996; Chiappetta and Koballa 2002; Shakhashiri 1992; Trowbridge, Bybee, and Powell 2000). While we were able to locate at least 10 identifiable merits associated with the teaching and learning of science using demonstrations (Majerich 2004), most of these claims remain unsubstantiated in the research. Figure 1 contains a facsimile of our previously published list.

Despite the scarcity of research to support these merits, science educators continue to champion the use of demonstrations as an essential tool for the teaching and learning of science (Buchanan et al. 2004; Shmaefsky 2004; Ophardt, Applebee, and Losey 2005).

Research has shown that, when the traditional lecture for large classes was accompanied by a few science demonstrations, the majority of students did not learn from these science events as typically performed

(Majerich and Schmuckler 2006). However, a recent study has shown that when instructional practices were modified to be more student centered (Bodner 1986), students did learn from science demonstrations and retained this information long after the instruction had ended (Buchanan et al. 2004). So, we decided to modify our Chemistry 51/52 course, a traditional lecture demonstration format, to make it more student-centered (Bodner 1986; Mintzes, Wandersee, and Novak 1998). Overall, our research goals were to

* begin to substantiate the 10 anecdotal merits associated with using demonstrations for the teaching and learning of science with students' perceptions of science demonstrations used in our course; and

* establish a research-based, student-centered instructional method using science demonstrations, improving students' mastery of content, for adaptation by all science teachers (NRC 1996).

Chemistry 51/52

This course is for nonscience majors, and is mandated by the provost's office to use a hands-on, participatory lecture demonstration technique using science demonstrations. Up to 200 students enroll in Chemistry 51; no more than 80 students enroll in Chemistry 52. One section of this course exists each semester; the course meets twice a week for a total of three hours and forty minutes. Herein is a discussion of the first semester of the course, with the larger group of students, taught with the traditional lecture demonstration method (TLD) and with a modification to the method, herein renamed the science lecture demonstration method (SLD), one year later.

As science educators are advised not to change curriculum in an attempt to compensate for poor student learning outcomes (Bodner 1986), we retained the same instructor, course content, textbook, sequence/location/number of science demonstrations, 10-minute daily quizzes (14 total), and number of examinations (3) for the TLD and SLD sections. The topics discussed were chemical and physical properties, chemical and physical changes, density, chemical reactions, laws of chemistry, cathode ray tubes, radioactivity, electromagnetic radiation, and atomic structure. …