disdain, they are often preferred by the learner because they seem more reasonable and perhaps are more useful for the learner's purpose (Mayer, 1987). These beliefs can persist as lingering suspicions in a student's mind and can hinder further learning (McDermott, 1991).
Before embracing the concepts held to be correct by the scientific community, students must confront their own beliefs along with their associated paradoxes and limitations and then attempt to reconstruct the knowledge necessary to understand the scientific model being presented. This process requires that the teacher:
Identify students' misconceptions.
Provide a forum for students to confront their misconceptions.
Help students reconstruct and internalize their knowledge, based on scientific models.
These steps are discussed throughout the remainder of this chapter.
Example of a Factual Misconception
A grade-school geography teacher once informed my whole class that the Gulf Stream is simply and entirely the Mississippi River, floating across the surface of the salty Atlantic all the way to Norway. I duly learned that, and neverthought about it again. It sat unexamined and unchallenged in my head for several decades, until the subject arose in a discussion with colleagues, and up it came like some weird deep-sea fish; I had only to mention it to be roundly hooted (by myself as well after giving it a half-second's thought). I was impressed by the clarity and circumstantial detail with which that fragile "unfact" was preserved for decades in my head; I bet there are others, and I bet we all have them. There may be families of them, lurking like coelacanths in the collective depths. I know there are twenty or thirty of us out there who either have dredged up and exploded the Gulf Stream heresy, or are still carrying it around in tact (Blackburn, 1995).
Before misconceptions can be corrected, they need to be identified. Many researchers and teachers have compiled lists of commonly encountered misconceptions (see sidebar at the end of the chapter). A number of professional societies have developed conceptual tests which allow you to identify students' misconceptions; we urge you to consult the organizations in Appendix B for more information. Additionally, small group discussions and office hours provide effective forums for identifying student misconceptions. With practice and effort, a teacher can learn to probe a student's conceptual framework (often by simply listening) without resorting to authority or embarrassing the student. Mazur has found a way to help students check their conceptual frameworks even within the large lecture format (see the sidebar in Chapter 3). Hake (1992) has used introductory laboratory exercises to help students test their conceptual bases for understanding motion. Essay assignments that ask students to explain their reasoning are useful for detecting students' misconceptions. These essays and discussions need not be used for grading, but rather can be used as part of the learning process to find out what and how your students are thinking.
Misconceptions can occur in students' understanding of scientific methods as well as in their organization of scientific knowledge. For example, students in a science class will often express disappointment that an experiment did not work. They do not fully understand that experiments are a means of testing ideas and hypotheses, not of arriving at an expected result. To the scientist, an experiment yields a result which needs to be interpreted. In that sense, each experiment "works," but it may not work as expected.
It is useful to review and think about possible misconceptions before teaching a class or laboratory in which new