School Science and Mathematics

and the degrees of freedom of a rigid body is a splendid exercise in reasoning for an advanced student. A similar discussion is wholly out of place in an elementary book, even for college students, and the deduction is usually so incomplete that it not only does not inform but fails to convince. Why not state both the principles of equilibrium of a rigid body baldly as experimental laws, and begin right there?

In a school course in physics, one should keep very close to an experimental basis with as little theory and mathematical deduction as possible. One should emphasize the great quantitative laws, however, but be very careful not to let them become formulae. In mechanics, one should emphasize equilibrium of forces, work and energy. One should introduce conservation of energy as early as possible and use it as the connecting thread for the whole course. Properties of matter are easily treated experimentally-particularly hydrostatics and gases-and so is heat. One should deal very lightly with electrostatics and magnetism and dwell on the fundamentals of direct currents. Periodic motion and waves should be taken up descriptively, defining the technical properties frequency, wave-length, etc., and calling attention to energy changes in vibrations and the propagation of energy by waves. Dwell on the physical explanations of lenses and mirrors and generally emphasize physical rather than geometrical optics. Give a great many simple numerical problems, but avoid formulae, except possibly a few expressions of very frequent occurrence, and these only allowed after many similar examples without formal statement of the equation. One should be very particular about units, and that the student understands the arbitrary nature of the process by which a number is made to represent a concrete quantity. He must also be accustomed at the start to the fact that an equation representing a law will vary with the units, so that the law is the thing to learn, not the equation.

Avoid formal definitions, but be very careful in the use of terms to follow the precise usage of the science. For instance, one should never use "power" except for rate of work. Instill the correct significance of a term and not an analogy. For example: An electromotive force is often described as a "pressure," forcing the current through the wire. The energy relations of the circuit present no greater difficulty and lead to a correct idea of e. m. f. as the amount of energy furnished the circuit by the source of energy per unit charge passing through.

The

As in the case of mathematics, the college entrance examination would have to be shaped to encourage such a course. papers now given seem vastly better than those in mathematics, but there should be more descriptive questions and fewer for which formulae can be crammed. For example, one might ask such questions as: "What three fundamental phenomena combine to produce the increasing resistance experienced in pumping up a tire? State the laws of these phenomena and the names by which these laws are known." Or "Explain fully why a distant object may be seen clearly through a convex lens if far enough from the lens or near enough to it, but becomes blurred at an intermediate distance.”

Laboratory Work: The laboratory work should be largely qualitative and consist of many short and simple experiments rather than elaborate ones. The apparatus should generally be simple and all parts readily visible. But whenever measurements are made, reasonable care and precision must be insisted upon, to train the faculties and to avoid the formation of careless habits. A neat and systematic original entry, curves well plotted to intelligently selected scales, and computations neatly entered, should be insisted upon. Mental arithmetic, logarithms and the slide-rule should be the only methods of computation tolerated, and the observance of significant figures should be taught. The student should be taught to criticize his own work and that the importance of a given mistake depends on its proportion to the quantity sought.

The school should, however, not shirk its share of the duller drill work of actual training in simple, scientific technique. Not only should the student be taught such things as simple glass blowing, electrical connections, etc., which have some fun in them, but should be drilled in the precise and correct use of the commonest scientific instruments, which require no theoretical knowledge whatever. For example: Measuring time intervals to a fraction of a second with an ordinary watch; correct and incorrect use of a rule, and eye estimates of fractions of a division; testing a thermometer, reading it to a tenth of a degree, and a reasonably sound technique in its use; reading a barometer and correcting it for temperature; use of calipers, including verniers; how to focus a microscope or telescope; weighing rapidly and up to the accuracy of the balance provided. He should from the start be taught the falibility of instruments and form the habit of

noting zero readings and making simple scale corrections. In other words: "Start him right!"

Summary: If four science units are accepted for entrance they should be modified so as to include:

1. A course in general science intended to familiarize the pupil with the most obvious natural phenomena, without reference to the science under which they are commonly classified, and also with the characteristic properties of common objects and materials. It should not be of the "project" type, but projects may be assigned for outside reading or as subjects for compositions.

2. A more systematic course in some one science applying the knowledge gained in general science.

3. A course, which might be styled "physical science" combining both physics and chemistry and intended simply to give that fundamental knowledge of each which is essential to the intelligent study of the other. That is, it should be preparatory to the college courses in these subjects in the same way that the general science introductory course is preparatory to course (2). It differs from the first course by being more advanced and thorough, but must on no account forestall or be an abridgment of the college courses. The laboratory work should be illustrative and simple, and such as to demand little theoretical knowledge, but it should include training in simple laboratory technique, and care should be taken that good habits are formed.

4. A course in mathematics intended specifically to prepare the students for the study of science in college.

It is intended that the last two courses shall be taken simultaneously in the last year before entrance. A high school student who does not expect to go to college might advantageously take the first two courses, and possibly that in mathematics, but a more practical type of course should by all means be substituted for that in physical science as outlined.

SODIUM WIDELY DISTRIBUTED

It forms

The element sodium is very widely distributed in the earth. about 2.36 per cent of known terrestrial matter, according to the United States Geological Survey, and is the most abundant of the alkali metals. Sodium appears to occur in nature only in combination with other elements, if its alleged occurrence as the free element in blue rock salt is neglected. It is an important constituent of the feldspars and several other insoluble minerals from which sodium salts are not extracted commercially but wnich are nevertheless regarded as the ultimate source of the salts that are soluble in water.

TESTS IN BIOLOGY AND GENERAL SCIENCE.
BY A. B. WELLS,

Concord Normal, Athens, W. Va.

The ordinary examination is being replaced more and more by tests patterned after the general intelligence tests.

The advantages of the new style of test are the covering of more subject matter in a given time, the greater speed and accuracy in grading the papers and the greater diagnostic value of the papers. The main objection to the new style of test is that the wording is fixed, giving the pupil no chance for the original expression. It is also claimed that the new test is a memory test and not a thought test, but my experience leads me to believe that such is not the case. Lack of thought was responsible for many errors in the answers which were correct.

I am not familiar enough with the many texts used in biology and general science to formulate a general test for a year's work in either of these subjects but I have made out six-weeks period tests and semester tests based on the tests I was using, with results very satisfactory to me. The text book in biology was A Civic Biology by George W. Hunter and the text in general science was Caldwell and Eikenberry's General Science.

In the semester tests I avoided true and false statements altogether as I believe their diagnostic value is very poor. A student who really knows 50% of his subject is likely to get a score of zero by subtracting the wrongs from the rights, in scoring.

The mutilated sentences were used entirely in the semester tests, as I got the best diagnostic results from them in six-weeks period tests in which I used true-false statements, selection of words in completing sentences, and mutilated sentences.

In choosing sentences the aim was to use those which expressed the most important principles and facts.

The sentences were mimeographed at an expense of about five cents a pupil for 100 pupils.

Copies of the tests compiled and used are appended.

The semester test was given only to students averaging less than 85% or BB for the semester as all students averaging 85% or more were exempted.

BIOLOGY TEST No. I.

Fill in the blank spaces in the following sentences with the proper words.

1. The process by which two gases or fluids separated by a

tend to pass through the

called

2. Root hairs give off a small amount of alkaline phenolphthalein solution

and mingle with each other is

3. The elements found in plant protoplasm are 1.

........ which turns a pink

and 10.

4. Plants which combine with the ability to scatter many seeds over a wide territory the additional characteristics of rapid growth, resistance to the dangers of extreme cold and heat attacks of enemies, inedibility and peculiar to cross pollination or

pollination are usually spoken of as 5. The compound leaf of the poison ivy has compound leaf of the Virginia Creeper has

Linen is made from

7. A substitute for olive oil is made from

leaflets but the leaflets.

seed.

8. Black and red pepper, mustard, allspice, nutmeg and vanilla are made from