主题：Chemistry Is Not a Laboratory Science

以后可以不做实验了
化学不需要实验？  [ 日期：2005-10-06 ]  [ 来自：论文阅读 ]俄勒冈州州立大学的Stephen J. Hawkes发表在J. Chem. Educ.(2004)上的一篇文章，认为化学实验教学既不能加深学生对基础理论的理解，甚至对于提高学生的其他技巧也没有帮助，只学到了一些最基本的操作技能，而这些技能他们早就会了，因此没有必要再次掌握；特别是对于非化学专业的学生就更加没有必要；对于一些基本的操作和实验效果，完全可以通过计算机模拟来解决；反之，开展过多的实验既浪费时间也浪费资源，甚至学生也不会喜欢(看来美国的学生愿意读化学的人也很少 )。


Chemistry Is Not a Laboratory Science
by Stephen J. Hawkes

Chemistry existed before there were laboratories, before there were humans, before there was life. Chemistry is the combination of principles and facts that caused the formation of the earth and its layering, that governs the ecosystem, and that underlie the properties of materials and of living organisms. Duplicating what we chemists do in our laboratories (or what chemists of earlier generations used to do) does not enhance students’ understanding of chemistry’s centrality, but makes chemistry an irrelevance.

Laboratory classes do not help students to understand how chemical principles affect their universe. If labs are cleverly arranged and courageously taught, they can help in promoting interpretation and design of experiment but they are not useful in learning other aspects of chemistry. Interpretation and design of experiment is effectively taught using computer simulations (1), avoiding the great expense and frustration of a lab. Non-majors have no use for the manipulative skills that they may learn in a chemistry laboratory.

For research on the effectiveness and usefulness of laboratory instruction, we may look to McKeachie’s reviews of laboratory classes in science (2). Several studies showed that laboratory work made no significant difference in tests of information, practical application, scientific attitude, or laboratory performance. McKeachie concludes, “While reviews of research on laboratory teaching find that laboratory courses are effective in improving skills in handling apparatus or in visual-motor skills, laboratories are not very effective in teaching scientific method.”

However, McKeachie goes on to cite other studies that show “that the effectiveness of the laboratory depends on the manner in which the work is taught.” Problem-solving methods are superior to more conventional systems in teaching to “apply principles of physics in interpreting phenomena” and in developing ability “to design an experiment.” I do not believe that these skills are useful enough to non-majors that they should be required to take a lab course, or that we should provide it in preference to the other teaching for which time and resources could be used. If it is held that we should, then McKeachie’s findings, which can be assumed to apply also to chemistry, support the lab-centered curriculum and the inquiry approach in specifically meeting these two objectives. However, at least one of them and probably both of them can be met by computer simulations.

It is often urged that chemistry is a laboratory science, and that students therefore need a hands-on laboratory experience. Whether this follows depends on the students’ reasons for studying chemistry. The non-major presumably studies chemistry in order to gain a better understanding of the universe, the earth, its ecosystem, and the mechanisms of life. The available evidence fails to show that this is enhanced by hands-on laboratory instruction. Honesty should demand such evidence before students are compelled to such instruction.

Some students would profit by understanding how the chemical structure of a substance affects its macro-properties such as its viscosity, malleability, permeability, color, or susceptibility to corrosion and how these may be enhanced or reduced by chemical manipulation. These relations are readily illustrated by reference to students’ experience with familiar phenomena such as the viscosity of molasses, the malleability of lead, the permeability of plastic to water as in a water bed, and the corrosibility of iron. It has not been shown that such understanding is improved by laboratory work and, judging from McKeachie’s review, it is not.

The enormous expenditure of time and treasure and student dislike of laboratory teaching demands substantial evidence that it has value commensurate with its cost and with the loss of subject matters that must be omitted to make time for it. If we insist on it, we need a better excuse than the assertion that chemistry is a laboratory science. For the overwhelming majority of our students, it is not.

Literature Cited
1. Martinéz-Jimenez, P.; Pontes-Pedrajas, A.; Polo, J.; Climent- Bellido, M. S. J. Chem. Educ. 2003, 80, 346–352.
2. McKeachie, W. J. Teaching Tips: A Guidebook for the Beginning College Teacher, 7th ed.; D. C. Heath: Lexington, MA, 1978, Chapter 16. Gibbs, G.; McKeachie, W. J. Teaching Tips: Strategies, Research, and Theory for College and University Teachers, 10th ed.; Houghton-Mifflin: Boston, 1999, Chapter 12.