What structure of information does a student obtain when he or she learn fluid engineering? In this paper, undergraduate students who had learned physics at their high schools were recruited as subjects and knowledge structurs about fluid engineering were investigated. The problems used in experiment were textbook problems, and protocol analisys was adopted to clarify students' processes to solve the problems. While students who had not taken any fluid engineering course remembered their naive physics at their problem solving, students who had passed the course suggested that they had their own structural knowledge and used systematic ways to obtain solutions.
