The Causation Of Difficulties In Mechanical Energy Teaching: A Multidimensional Study

Energy is one of the most important and abstract conceptions and mechanical energy is the most universal energy . The conception teaching of mechanical energy in senior middle school is very important ,while the teaching situation is not well-tried. In order to probe into why students studied difficultly,via literature, investigation, interview, questionnaire, many research on misconceptions, development histories, content-compiling, experiments, instrumen related to energy, work and mechanical energy conceptions have done. Based on these , new research should be make to improve the instructional design focus on mechanical energy .First, literature research on concept comprehension and teaching of energy reveal that students mostly cofuse the conceptions of force and energy ,can not understand law of conservation of energy ,can not resolve problems with law of conservation of energy in context because of misconceptions. The traditional teaching on energy always let students do calculation in utopian context aparting from experienceand and the effect is not good enough.To understand the concept of energy deeply, students must link energy with work, relate energy transformation with"real world".There are a long development history on work and mechanical energy in physics history.We know that the combination of the two conceptions is a milestone in the long development histories of work and mechanical energy, from slowly to fast till the combination of the two conceptions. Because of the similarity between students'knowledge construction and the form of conception in scientific history, the combination of work and energy is key to learn the conception of the mechanical energy.A study on senior physics textbook indicate that ,on content, the conception teaching of work is angularity in traditional textbook, which is short of profundity to students, and the relationship between work and energy is given directly without enough proof while students understand kinetic energy and potential energy mest base on therelationship between work and energy; on method, the students learn knowledge by theory analysis without enough experiments . Aiming at enhancing students'scientific accomplishment, many betterments are made in the new physics curriculum ,but the attention of how to improve the teaching of conceptions on work,energy and mechanical energy is absent. On another hand ,the students are difficult to accept a concept unconditionally,which is against the students'oppugn spirit and the aim of the new curriculum.The investigation shows that the students have difficulties in understanding work, energy, gravity potential energy,law of conservation of mechanical energy. there are improving interspace in mechanical energy teaching. On the base of these research,this paper give many measures. on content,we should introduce these conceptions along their histories, with the relationships of work and energy ,to use for reference and gradually deepen ;on method,we should make the students construct knowledge by doing.The education not only concerns about the knowledge but about the study process to enhance the students'scientific accomplishment.At the end of the paper, some shortage and the following research orientations are presented.