高三學生液體界面現象迷思概念之研究

Abstract

本研究探究高三學生液體界面現象的迷思概念以及可能的來源。研究的對象為桃園市某國立高中三年級的學生共40名，研究方法為問卷調查及事後晤談。問卷為研究者自行設計含14題的開放性問卷，題目經過八位專家教師審查，具專家效度。研究發現迷思概念的來源及迷思概念如下：（一）概念誤用：1)『表面張力與浮力』之概念混淆：認為受表面張力作用的物體在水中會有部分的體積，受到浮力作用的物體則沒有在水中的部分；2)『內聚力與水壓力』之概念分不清楚：以水壓力的觀點來解釋內聚力，認為離液面越深，內聚力越大；3)『大氣壓力現象與毛細現象』之概念混淆：以先前所學的托里切利實驗來解釋管內液面上升或下降的情形；4)『濡濕現象與浮力』概念分不清楚：認為毛筆在水中不成尖形是因為受到浮力作用；（二）概念連結有缺失：例如對『能量』概念不甚了解，導致對許多概念的連結上有缺失:諸如『溫度越高，表面張力越大』、『沸點越高，表面張力越大』、『溫度越高，毛細作用越大』等；（三）對定義的不夠了解：例如1)物體在水面上才有表面張力；2)特殊液體不用放置物體就有表面張力；3)密度大的液體凝聚成球珠狀、密度小的液體灘成水膜；4)固體沒有表面張力；（四）由語言造成迷思概念例如認為『內聚』力就是作用力向內；（五）直覺的想法：自認為溫度越高，表面張力越大；（六）受經驗影響：沒看過水銀成薄膜，因此認為水銀皆凝聚成球珠狀；（七）教科書的影響：因看過類似的概念而影響即將學習的概念，如先前在教科書上看到力的方向為物體運動的切線方向，因而認為內聚力的方向是沿液面上升或下降的切線方向。本研究建議教學時要注意下列各項：1)強調相似科學概念之間的差異及原理；2)液體界面現象單元裡的許多概念皆與能量相關，要特別釐清其間的關係；3)以圖表幫助學生了解中文科學名詞的意義；4)課文中概念之間的關係需介紹清楚。The study explored the misconceptions and the sources of liquid interface phenomenon of the 12th graders. Forty 12th graders from the Taoyuan County were selected. Researcher self-designed a 14 items open-questionnaire and interview were adopted. The questionnaire had been reviewed by eight experts. Research findings were as follows 1) misuse of concepts: for examples i) the confusions between surface tension and buoyant force; ii) unclear concepts between cohesive force and water pressure; iii) misunderstanding between atmospheric pressure and capillarity phenomenon; iv) unclear concepts between wetting and buoyant force; 2) missing linkage among concepts: for example, the unclear concept of “energy”; 3) misunderstanding of definitions: such as i) the surface tension existed only when the object was on water; i) for special fluid there would have surface tension no need placing any object on it; iii) fluid with a high density would be condensed into a ball-shaped beads; iv) a solid had no surface tension; 4) language caused misconceptions: for example, in Chinese the “cohesive force” will be decoded as the inward force; 5) intuitive thinking: such as some students believed that the higher the temperature, the greater the surface tension; 6) affected by daily experience, such as no acknowledgement on how mercury becoming water film, hence students believed that all of the mercury condensed into ball-shaped beads; 7) the influences from textbooks, a first contact with related concept will affecting the building of on-going concept. The study suggested that teacher should pay more attention toward the following: 1) emphasizing on science concepts’ differences and principles; 2) the phenomenon of liquid interface are always related to lots of energy concepts, teacher should clarify their relationships; 3) teacher should help students understand the Chinese scientific terms with the aid of charts; 4) textbook should explain concepts relationship clearly and completely.