An Investigation On The Cognition Of Accelerated Concept Of Middle School Students

Acceleration is one of the basic concepts of mechanics, it is the bridge between force and motion, and it is also the key and difficult point in middle school physics teaching. In order to help students to form correct acceleration concept and improve the efficiency of classroom teaching, we need to explore the cognitive situation of acceleration concept in students’ minds,and reveal the law of cognitive development.In this study, we try to use the integrated research method of combining the methods of questionnaire and interview, with no formal learning concept of acceleration of the second and third year junior high school students and the students who have learned the concept as the research object, to explore the cognition of the concept of acceleration before and after the study of the high school students. First of all, with reference to the domestic and foreign research data on acceleration, carefully designed the questionnaire and launched an investigation. Then, a typical representative sample of the questionnaire was selected to conduct individual interviews,in order to probe into the process of knowledge generation in the students’ minds. Finally, the results of the survey using quantitative and qualitative analysis of the method, draw the conclusion of the study and put forward the corresponding teaching suggestions. The following conclusions are drawn from the study:1.After learning, the students get rid of the wrong cognition that depend on position to judge the speed, correctly understand the concept of instantaneous speed, and form a correct cognitive process.2.After learning students understanding to do uniform motion of the object acceleration is 0,can correctly distinguish between velocity and acceleration, but there are still students have the wrong cognitive that based on position, velocity to judge the acceleration, they simply memory rules and conclusions by daily life experience, from the surface level, according to the sense of judgment.3.After learning, most students get rid of the wrong cognition that regard acceleration "to increase the speed", they can know to the decreasing speed of movement of the acceleration, but they can’t understand there is acceleration when velocity direction change, understanding of vector still remain on the level of awareness of the size of the vector. The lack of knowledge of vector is the main difficulty for students to construct the concept of acceleration correctly. A few students are affected by the fixed thinking after their studies, and think that there is an acceleration in the motion of a single straight line.4.Before learning, there are four levels of students’ understanding of acceleration: accordingto one amount to understand the acceleration; according to two quantities to understand acceleration, a certain dominant amount; according to the two quantities understanding acceleration, where a constant amount, through the judgment of another; according to the ratio of the two relations understanding acceleration.5.After learning, students’ understanding of the physical meaning of the concept of displacement, velocity and acceleration is superficial, and it is easy to confuse these concepts.They get used to solve the problem with low levels of reasoning from the intuitive point of view or used the life experience directly solve the problem, but rarely from the perspective of the definition of acceleration to analyze the problem.For students to study the characteristics of the acceleration of the concept of cognitive process, put forward "to the students’ cognitive before teaching" as the starting point, etc. 5teaching suggestions.