Students' conceptions of chemical change
Students' conceptions of chemical change
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学生对化学变化的概念
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
C. W. Anderson
中科院分区：
文献类型：
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作者：
Joseph J. Hesse;C. W. Anderson
100名高中化学学生完成了化学变化的一个单元，他们得到了一个书面文书，其中显示了三个氧化还原反应，并要求他们解释它们。代表一系列成就水平的11名学生被选中进行更深入的临床访谈，他们解释自己的反应，评价他们的反应质量，并将其与其他假设的反应进行比较。访谈结果显示，学生普遍在三个不同的认识层面上遇到困难：
1.化学知识。大多数学生未能援引原子和分子作为解释性的结构，即使他们在化学课程中强调了这一点。一些学生还列出了“物质”，如热，冷，或衰变作为反应物或产物。
2.保守推理。许多学生无法预测或解释化学反应中的质量变化。他们最常见的问题包括：（a）倾向于将生锈等化学变化视为形式或状态的物理变化，以及（B）未能理解反应中不可见（在这种情况下是气态）反应物或产物的作用。
3.净化的理想。许多学生表现出对基于与日常事件的肤浅类比的解释的偏好（例如，生锈就像腐烂）而不是基于化学理论的解释。
在接受采访的11名学生中，只有一名学生在所有三个级别上都掌握了该单元的内容。这项研究和其他研究的结果表明，需要在化学教学实践中进行实质性的修改。
One hundred high school chemistry students who had completed a unit on chemical change were given a written instrument in which they were shown three oxidation-reduction reactions and were asked to explain them. Eleven students representing a range of achievement levels were chosen for more intensive clinical interviews in which they explained their responses, evaluated the quality of their responses, and compared them to other hypothetical responses. Interview results revealed that students commonly experienced difficulties at three different epistemological levels:
1. Chemical knowledge. Most students failed to invoke atoms and molecules as explanatory constructs, even though they had been emphasized in their chemistry course. Some students also listed “substances” such as heat, cold, or decay as reactants or products.
2. Conservation reasoning. Many students could not predict or explain mass changes in the chemical reactions. Their most common problems included (a) a tendency to treat chemical changes such as rusting as physical changes in form or state, and (b) failure to understand the role of invisible (in this case gaseous) reactants or products in the reactions.
3. Explanatory ideals. Many students demonstrated a preference for explanations based on superficial analogies with everyday events (e.g., rusting is like decay) over explanations based on chemical theories.
Only one of the 11 students interviewed demonstrated mastery of the unit's contents at all three levels. Results of this and other research indicate a need for substantial revision in chemistry teaching practice.