Physics is an intellectually demanding discipline and many students have difficulties learning to deal with it.  Further, our instruction is often far less effective than we realize. Indeed, recent investigations have revealed that many students, even when getting good grades, emerge from their basic physics courses with signification scientific misconcepts, with prescientific notions, with poor problem-solving skills, and with an inability to apply what they ostensibly learned. In short, students' acquired physics knowledge is often largely nominal rather than functiional.

This situation leads one to ask: Why is this so, and what can be done about it? More specifically, it has led me to address the following two basic questions: (a) Can one understand better the underlying throught processes required to deal with a science like physics? (b) How can such an understanding be used to design more effective instruction?

These are the questions which have been the focus of my work during the last several years and which I want to discuss in this article.