The Chemistry Student HOW TO STUDY CHEMISTRY Let us say at the outset that we have discovered no royal road to learning. There is no method of study which obviates the necessity for hard work on the part of the student. Yet study can be made easier in the sense that a certain amount of effort rightly directed will accomplish far more than the same amount mistakenly, though earnestly, applied. Professor George FiUmore Swain has written an excellent little pamphlet on "How to Study"' which we heartily recommend to all students. The present article is based largely upon portions of Professor Swain's booklet, with some interpolations and comments intended to apply more particularly to chemistry.
The Proper Mental Attitude Professor Swain begins by counseling the student to adopt the proper mental attitude. To this end it is necessary that the student distinguish between mere reading or even memorizing, and understanding. No doubt every one finds himself a t times reading merely wards or phrases without understanding them, reflecting about them, or translating them into terms which are intelligible t o his understanding. Such reading is worse than useless; i t leads t o actual mental injury. Whenever we find ourselves doing this we should therefore arouse ourselves, make an effort of the will, and concentrate our attention upon the subject, insisting upon understanding it. If for any reason we are unable t o do this, we should close the book, take some exercise or remation, or a t any rate do something else, for we are not a t the moment fitted for study. We might as well eat sawdust and deceive ourselves with thinking that we are taking nourishment. I t is not what is read or what is remembered, hut only what is understood, that gives power.
Furthermore, he must learn to distinguish mere fads from conclusions or opinions. Mere facts, some of which may be the result of laborious investigation, may be accepted without verification, if the authority is good. . Very different are conclusions or opinions deduced from facts; and logical conclusions are very different from mere opinions. The facts may be sufficient t o prove logically a certain couclusiou. On the other hand, the facts may simply give reasouable ground, or appear to give reasonable ground, for a certain opinion, though they may fall far short of demonstration. The student must, therefore, discriminate constantly between mere statement of facts, necessary d u s i o n s which fallow therefrom, and mere opinions which they seem t o render reasonable.
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Most important of all, the student should maintain a questioning attitude of mind. He should always ask himself, regarding any statement which he reads, whether there is a reason for it, and if there is, whether it is inherent in the nature of things, so that he might independently arrive at it, or whether it follows from facts which the writer has observed.
He should ask himself whether there is any connection between a new fact or idea which he encounters and others which he has previously learned and if so what that connection is. When he encounters a statement he should consider not only the statement itself but its implications. Thus the facts that mercury has a density of 13.55 and iron a density of 7.85 imply that iron will float on mercury. The atomic theory of t h e nature of matter implies the laws of definite and multiple proportions. (How?) When the student encounters a law he should ask himself whether that law has been stated as generally as possible or whether it is a special case of a broader and more general law. (Compare Richter's law with the law of chemical equivalents.) Methods of preparing compounds should he sczutinized wiaha xiew tadete&nivg,whetker they are unique or general. Ifthemethodemployed in a catain.caseis.not general, what are the general methods'for that t y p e d preparation?: ..Could one of them be employed? If not, why not? If so, what are the advantages of the special method? Studying Understandingly Professor Swain emphasizes the fact that to study understandingly the student must cultivate the habit of forming definite ideas. It does him no good t o read that "matter is disaete rather than continuous'' if he gets no clear idea of what is meant. The student should resort to the dictionary as frequently as necessary to make sure that he knows the exact meanings of the words which he encounters. He should learn to distinguish between words of definite meaningand words which are vague or ambiguous. Also he should learn to recognize words which have definite meanings hut which are often wrongly or loosely applied. Thus, a "strong" acid is not synonymous with a "concentrated acid, nor a "weak" base with a "dilute" base. Furthermore, he should learn to recognize words which express single ideas, and words which can be analyzed into simpler components. Thus "momentum" involves "mass," "time" and "distance," for momentum is the name given t o the mathematical product of mass X velocity, and velocity is distance traveled in unit time. Fmally, he must realize that naming a thing, phenomenon, or condition is not always equivalent to explaining it. To say thattcertain changesin a system come about by reason of "alterations in the thermodynamic environment" ,explains 1 nothing.
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The practice of studying good definitions and determining the necessity for every term included is a great aid toward forming definite ideas. It is even more helpful, if you have access to a textbook which does not insist upon confronting you with definitions a t every turn, to study the discussion until you understand it thoroughly and then frame your own definition. Test it by trying to think of exceptions. When, finally, you have made i t as nearly perfect as possible, turn to some standard authority and compare his definition with your own. Are they essentially the same? Has he included some qualification or limitation which you have omitted? The habit of memorizing definitions for reproduction upon demand, without thoroughly understanding the thing or idea defined, is slow mental suicide. If you thoroughly understand the matter you study you need never memorize a definition, for you will always be able to frame your own. The student should also learn to state things in different ways and from different points of view. This involves a recommendation which we have already made--to consider the implications of a statement. Professor Swain quotes an amusing anecdote related by Wm. James in his "Talks to Teachers." A friend of mine visiting a school was asked to examine a young class in geography. Glancing at the hook, she said: "Suppose youshould dig a hole in the ground, hundreds of feet deep, how should you find it at the bottom-warmer or colder than on top?" None of the class replying, the teacher said: 'I'm sure they know, but I think you don't ask the question quite rightly. Let me try." So, taking the hook, she asked: "In what condition is the interior of the globe?"and received the immediate answer from half the dass at once: "The interior of the globe is in a condition of igneous fusion?"
Ridiculous as this incident may seem, it has its parallels daily in highschool and college chemistry classes. In learning to state facts in different ways the student should remember that "mathematics is a language," and one with which the man of scientific occupation or interests must become thoroughly familiar. Not all principles are capable of mathematical expression, but those mhich are may be stated mathematically with elegance and precision. Learn t o translate equations into words and vice versa. It is also well to express ideas negatively or in reverse and t o see how far the reverse statement holds true. Thus, all chemical compounds are homogeneous substances. Is it correct to say that all homogeneous substances are chemical compounds?
Classify and Correlate Try t o classify and correlate what you learn. Especially try to note how the facts which you encounter can'be explained by the general theories yon have learned. Professor Deming gives an excellent example in his
"General Chemi~try,"~ when he compares the properties of gases with the molecular theory. R o w THE MOLECULAR THEORY EXPLAINS TKE P R O P ~ T IOP E SGASES
Observed Fads
Explanation
Gas pressure. Diffnsibilitv. Compressibility. I Liquefaction. (;B.s condense to form liqllids whencompressed and cooled Increase of tmssureor volume with in( increase bf temperature (Charles' Law). Decrease of volume with increasing pressure (Boyle's Law). ~
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Gases are cwled but slightly by expanding into a vacuum (Joule's Law).
Deviations from Laws of Charles and Boyle.
Each gas, in a mixture of gases, exerts the same pressure that i t would if i t occupied the whole space alone (Dalton's Law of Partial Pressures).
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The preceding facts viewed in relation t o the laws of energy.
Bombardment of walls by molecules. Molecules in raoid motion. Large spaces between molecules. Molecules tend t o cohere when cloxly ~'ackrrl,especially a t low temperature-. hIolcculcs move more rmidlv . . at hiehpr temperatures. -
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Increased pressure canfines molecules in proportionately smaller volume. Molecules of a gas have hut slight attraction for each other, or tendency to cling together. If such attraction did exist energy would be absorbed in overcomAttraction or cohesion between molecules not altogether absent Volume 0 x 1 pied by molecules not altogether neglieible. " Molecules are so far apart that they move without interference from each other; and when they happen to collide, rebound without loss of energy. A given volume, under given conditions, . contains nearly the same number of molecules for all gases (Avogadro's Principle).
A Point to Remember The student should keep in mind that an elementary study of a subject is not a super!icial study. It is first necessary to lay a foundation and erect a skeleton before a finished structure can be attempted. Try to get a t the fundamentals of any subject which you study. We have exhausted neither the subject nor Professor Swain's recommendations, but perhaps we have offered enough for one sitting. At the risk of being accused of plugging for the publishers we urge all students to obtain a copy of "How to Study" and to spend about two hours in reading and digesting it. Thereafter an occasional glance at the outline in "'General Chemistry," Horace G. Deming, John Wiley & Sons. Inc. edition, 1925, p. 27.
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the front of the booklet should serve as a reminder to maintain proper habits of study.
Test Your Own Habits of Study Perhaps you have already learned to study properly. If so, you should find no difficulty in answering the following questions. 1. Here is a little exercise in logic. "To call you an animal would be to state the truth." "To call you an ass would be to call you an animal." "To call you an ass would be to state the truth." Where is the fallacy, if any? 2. Which is the better definitionpVMatter is that which can occupy space" or "Matter is that which occupies space?" 3. The space between the jacket and the flask of a thermos bottle contains a vacuum. Hence we may say that the vacuum occupies that space. Is it therefore correct to say that a vacuum is a form of matter? Why, or why not? (What is a vacuum?) 4. "All samples of a given compound contain the same elements, in the same proportion by weight." Does i t necessarily follow that all samples which contain the same elements in the same proportion by weight are samples of the same compound? If not, can you cite exceptions? (Ask an organic chemist.)
