以建構理論的觀點探討國中理化中密度與浮力的教學

In view of constructivism,the discussion of density and buoyancy in junior high school which involves in “teaching and learning”

江陳富(Chen_fu Chiang)

指導教授 ： 楊嘉喜

中原大學/理學院/化學研究所/碩士(2002年)

https://doi.org/10.6840/cycu200200149

摘要

摘 要
國中階段的學生在學習浮力概念時常遭遇困難，甚至，理化教師也覺得難於施教。本研究的研究目的在探討受試學生在經過認知衝突的實驗活動後概念改變的情形。進一步提出教導學生學習浮力概念的教學模式並且以能夠完整而清楚建構學生的浮力概念為目的。
本研究對象包括國一、國二、國三學生，由研究者設計一連串且有系統與浮力有關的情境、引導出學習者的動機，受試者面對情境加以推理詮釋，產生受試者的認知衝突，施測者再以與情境主題有關的實驗活動建立學生正確的概念，研究者利用前測與後測，甚至唔談評量去瞭解學生的想法，進一步建構出正確的概念。
從研究的結果分析中發現，學生面對情境中有關浮力及物體浮沈的解釋當中顯示，國中學生對於浮沈現象的錯誤概念相當多是由於對「密度」概念的不了解，無法區分重量與密度的不同，而非均勻系物體的浮沈是國中課本甚少提到的，其中平均密度的改變(體積或質量的變化造成的浮沈變化)更是學生較難理解的。另外，學生無法理解浮力的另一個重要原因主要在對物體作用力的理解不夠，原因可能是未具備牛頓力學的認知基礎，對力的分析無法掌握，建議教師應多設計具體情境讓學生熟悉作用力的內涵，以補救學生學習的困難。
最後，如何引起學生學習浮力的動機，讓浮力概念的學習，不再是課本中傾向教條式的說明，食譜式的實驗，本研究試著採用 STS課程設計即科學(Science)，技學(technology)，及社會(society)的簡稱，愈是社會化的情境愈是能夠引起學生的學習動機，教學方面採取P．O．E．C教學模式P(Predict)預測、O(Observation)觀察、E(Explanation)解釋、C(Comparison)比較，希望學生更容易從觀察比較中去澄清自已的觀念，也提供多元教學中多一種參考。
關鍵字認知結構，概念改變，建構，STS課程設計，P．O．E．教學模式，密度，浮力。

關鍵字

關鍵字:認知結構 ； 概念改變 ； 浮力。 ； 密度 ； 教學模式 ； P．O．E． ； STS課程設計 ； 建構

並列摘要

Abstract
Junior-high Students often come up with difficulty when it comes to learning buoyancy concept. Furthermore, Science teachers find it is difficult to teach the subject. This research is aimed at exploring the concept change when the students are confronted with the conflicts of their understanding of experiments. Furthermore, a teaching mode for buoyancy concept is given in the hope of helping student constructing a clear concept.
The subject of this research contains junior-high students at every grade. A series of systematic situations relating to buoyancy are devised in a hope to provide motivations to the learners. The researchers can make assessments based on this program. They are able to know what the students think so as to build up accurate concepts.
The findings of the research reveal that students are tremendously confused with the buoyancy and have difficulty in understanding of “density”. They cannot tell the difference between weight and density. The buoyancy of an inhomogeneous substance is seldom mentioned in the textbook. So the alteration of the average density (The alteration of volume or mass of a substance can cause a different buoyancy)
is beyond comprehension of the students. On the other hand, students do not possess enough basic knowledge of Newton’s dynamics, so they are unable to grasp the force in action.

In an end, students should be motivated to learn buoyancy, rather than learning from a textbook, doing experiments following a “cookbook”.
This research is designed with a STS program, namely Science, Technology and Society. A situation designed to be more societal may attract students. The teaching is combined with P.O.E.C teaching mode, namely Predict, Observation, Explanation, and Comparison. It is hoped, by this, that students can clarify their concept by their observation more easily, and it also serve as a reference in diverse teachings.
Key words: Recognition Structure, concept alteration, to structure (build up), STS program design, P.O.E. teaching mode, density, buoyancy.

並列關鍵字

P.O.E. teaching mode ； concept alteration ； STS program design ； density ； Key words: Recognition Structure ； buoyancy. ； to structure (build up)

參考文獻

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