九年級學生描繪力圖能力之探討

Abstract

本研究欲探討九年級學生固有的力學迷思概念類型及分布情形，並分析持有不同迷思概念的學生，在進行力圖分析時，是否會被特定的迷思概念干擾或產生其他影響。 研究首先以修改自Force Concept Inventory(FCI)的「力與運動物理觀念評量」，檢測46名九年級學生所持有的牛頓力學迷思概念並將其分類，並從各類型的學生，邀請2~3位表達流暢且具代表性的學生，讓學生完成「力圖分析評量」並進行測後晤談，以找出迷思概念與力圖分析的關聯性。 研究結果顯示：1. 經「力與運動物理觀念評量」(alpha信度值為.75)測得，學生主要具有「衝力迷思」及「作用力與反作用力迷思」。2.學生面臨相同概念但不同的情境的題目時，受各類迷思影響的程度也不同。3.學生容易將速度與加速度兩者混淆 。4.學生無法正確進行力圖分析的原因有二，其一為分析力圖的步驟有誤，一開始就列出所有已知力，再由牛頓三大定律去拼湊出未知的力，容易誤判摩擦力和空氣阻力的方向。其二為對各種力如正向力、摩擦力、浮力、磁力的認識不足，造成學生在進行力圖分析時，易誤判這些力的方向、或將不知來源與種類的力隨意以這些作用力解讀、或是直接忽略這些作用力。 學生遇到同概念卻不同情境、不同題型的題目時，有時會將之視為不同概念的題目，因而產生不同的解題特徵與解題步驟。因此在檢測學生所具有的迷思概念類型時，同一種迷思概念最好以兩種以上的情境、題型做檢測，方能精確掌握學生所具有的迷思概念。 另外，本研究分析出具特定力學迷思的學生，在特定情境下易持有之力圖分析解題特徵，將可提供第一線教師在教學時做參考，使其能根據解題特徵，找出學生可能持有的迷思。The purpose of the paper was to investigate the types and the distribution of misconception the ninth-grade students about the topic of mechanics. The researcher examined the interference or the influence of the certain misconceptions shown by the students with different types of misconceptions when they were doing analysis of free-body force diagram. First, the paper was based on a modified adoption of Force Concept Inventory(FCI), examining the misconceptions of ninth-grade students, and classifying them. The researcher invited 2 to 3 students who are representative in various types and can express their ideas clearly, and then interviewed them. After examining and interviewing, the analysis was to identify the relation between misconception and free-body force diagram analysis. This paper indicated the following results. First, with FCI, it is certain that students possess misconception of impetus and action/reaction pair mostly. Second, the impetus and action/reaction pair are not an important factor while students were doing force diagram analysis. Third, the misconception of mechanics was a major factor in students’ free-body diagram analysis. With the unclear ideas between force and motion, the students with this misconception made a wrong cognition that composition of forces determines the direction of the movement and composition of forces was a kind of force. Finally, there are two factors influencing the process of making correct free-body diagram analysis. One, the procedure of analysis was not correct. Students listed all the forces and then guesses the unknown force according their understanding about Newton’s laws. They made a wrong judgment on the direction of friction and air resistance. The other factor is the unclear and poor concept of forces, such as normal force, friction, buoyancy, and magnetic force as well. The inadequate cognition determined the way students made analysis. The wrong direction of the forces was determined. Moreover, the forces were easily omitted or arbitrarily interpreted.

The result shows that students will take different procedures and show different action for answering question although the questions are based on the same concept, but set in different situations or types. Therefore, it is suggested that teachers whose aim is to identify the misconceptions of students correctly can set the questions with various situations or types but based on the same concept. In addition, the findings which were revealed when students did analyses can be helpful for teaching. Teachers can identify the misconception according to the action of answering questions.