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Copyright © 2007 jsd

1  Chemistry With or Without Atoms

Nowadays, any sensible understanding of chemistry revolves around atoms and molecules.

However, on special occasions it is an amusing exercise to ask how much chemistry depends on knowing the size of atoms, and how much doesn’t.

This exercise is suitable for people who already know a thing or two about chemistry, including atoms. It is not a suitable way to introduce the subject, for reasons discussed in section 2.

This exercise is a two-edged sword: It is amusing to see how far we can go without atoms, but it is just as important to see which parts of chemistry really need to be explained in terms of atoms.

As a starting point, we examine the following corresponding terms, and note that the correspondences are useful but not exact:

macroscopic microscopic
element     →     atom
compound     →     molecule

Describing chemistry in terms of ancient continuum terminology such as “element” and “compound” brings to mind what Dr. Johnson said about a dog walking on his hind legs: It is not done well, but you are surprised to find it done at all.

It’s a bad workman who blames his tools.

2  Pedagogical Implications

I have the greatest respect for real history and real historians.

The real history of science is not simply monotonic forward progress. Instead, the real “progress” of science has required much backtracking out of blind alleys, as explained in reference 1 and elsewhere. The scientists of yesteryear we confused about a lot of things. That does not mean they were stupid; on the contrary, it is a testament to their skill and dedication that they were able to accomplish so much despite the great handicaps and impediments that afflicted them.

There is no law that says pedagogy must recapitulate phylogeny.

Some teachers claim they are using the “historical approach” as a way to organize and motivate the study of the subject. I say they should be allowed to use that approach if they choose, but they shouldn’t be forced to use it.

3  References

1.
Thomas Kuhn, The Structure of Scientific Revolutions
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Copyright © 2007 jsd