ABSTRACT
This chapter discusses evidence from problem-solving case studies that indicates that analogies and extreme cases can play important roles as forms of nonformal reasoning in scientific thinking. Examples of experts spontaneously reporting the use of imagery while making predictions are also discussed, motivating the hypothesis that experts sometimes use elemental concepts at a perceptual-motor level; these are commonly referred to as physical intuitions. Although some people may consider these methods more “casual” than deductive reasoning, one of my purposes is to describe how expert problem solvers can rely on them in a rather formal context, the context of doing their best to think about a physics problem. In a second section, I discuss attempts to utilize nonformal reasoning in science instruction and describe a study that shows significant differences in students’ performances that favor experimental high school physics classes using these methods.
