Page:Popular Science Monthly Volume 86.djvu/171

Rh without understanding either their pedagogical purpose or their theoretical significance. One science teacher speaks of another as being "well up" in science, because he knows the names of minerals or of spiders that you and I never heard of; or he knows all the stages in the life-history of some very rare red sea-weed. Here science is confused with erudition that happens to concern itself with objects of nature rather than with words out of books; but erudition is not science in the one case any more than in the other.

Another defect in much of our current science teaching lies in the fact that the method of the experiment, which is supposed to be one of the fundamentals in modern science, is often taught as a matter of manipulation rather than as a matter of thought. Thus, in presenting certain types of experiments, the negative instance or control is entirely ignored. A chemical test is given, let us say, for the identification of starch, or for determining its presence. The teacher shows that the addition of iodine solution to starch produces a blue color; the application is immediately made by placing some iodine on bread: the conclusion forced out of the minds of the unsuspecting victims is that bread contains starch! I quote from an elementary biology by well-known teachers:

1. Put a small amount (size of pinehead) of corn starch in a test tube, add water, shake the mixture, and boil it over a gas flame. Pour into the starch mixture thus formed a few drops of iodine. What color is produced?

2. Try the effect of iodine on each of the other food substances as follows: Put a small amount of grape sugar into a test tube; into a second tube put some white of egg (protein); into a third some fat or oil; into a fourth some mineral matter (salt); and into a fifth some water. Add a little water to each and boil as in 1 above to cook each nutrient. Add a drop or two of iodine solution to each tube.

Do any of the colors thus produced resemble at all the color resulting from the addition of iodine to starch?

3. From the preceding, state how you can determine whether or not a substance contains starch.

Or we are to show that water is essential to the germination of seeds; and we are content to rest the case on the fact that seeds supplied with water did under certain—but undefined—conditions actually germinate; or we may accept the conclusion on the fact that seeds without water did not germinate—overlooking the equally obvious fact that certain seeds without soap-powder or star-dust also failed to germinate.

One biology teacher, after drilling the simple chemical tests for the nutrients, proceeded to apply the acquired knowledge in true pedagogical fashion, by testing an "unknown." The unknown proved to contain both starch and proteins. The application came when the teacher asked, "Well, then, is this substance fit to eat?" An affirmative answer was promptly forthcoming, and there ended that lesson. In an