Science for beginners; a first book in general science for intermediate schools and junior high schools

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Preface

Only a generation ago, it was the prevailing idea that all instruction in schools and all learning by pupils should be con&ied to the schoolroom and to books. Nature study was unknown, except that once in a while curious relics from foreign countries were brought in to emphasize some phase of the pupil's study. A little later more material was taken into the classes and used to verify to some extent the statements of the books. But these were only fragments of the part of nature which they represented, and for that reason aroused very little interest in either teacher or pupil. Out of this somewhat fragmentary study has grown the laboratory method which is used in the better schools at the present time. But even yet there is not enough use of the real thing and the whole thing s The material for study is gathered by the teacher or is furnished by the school authorities, and the pupils are required to handle only those portions which will illustrate the point under discussion.

Gradually, however, teachers are coming to see that to get the best results the pupil must, whenever possible, gather his own material. When this point is conceded, it is readily agreed that the pupil may oftentimes study his materials to greater advantage in their natural environment. The inevitable conclusion to be drawn from all such reasoning is that in many cases the study of nature requires that the pupil should go out of doors and, under proper guidance, observe, examine, describe, reason upon, and finally draw his own conclusions concerning the matter in hand.

It is suggested that the less help the pupil has the better he will do his work, provided he is given necessary instructions and encouraged to go on to the end of his study. After he has exhausted his own resources in a given problem, it is the teacher's part to contribute by supplementing and enriching the knowledge which has been obtained by the pupil.

•• • iv Preface

But until the work of the pupil is done, the r61e of the teacher should be one of masterful inactivity.

The teacher is asked to keep in mind that the chief purpose of this book is not to give the pupils a large amount of information, but rather to introduce them to a method through the use of which they will acquire the habit of gaining information for themselves. The scientific method, by which is meant that methodical procedure which is more and more coming to be used in all lines of human activity, is most easily applied in the field of the natural sciences, and the pupil can best learn the method of the scientist by using the material with which the scientist works.

The author makes no apology for the constant use of the direct address. The book is a direct message to the user of it, and it is to be hoped that the teacher will encourage the idea that here is the boy^s and the girl's own book.

For helpful suggestions the author is under obligations to Miss Marie K. Dunn, Teacher of Science, Junior High School, Solvay, New York; Donald P. Boyer, Principal Bellevue Junior High School, Richmond, Virginia ; Stanley S. Foote, Lincoln Intermediate School, Santa Monica, California ; Harry A. Richardson, Teacher of General Science, Junior High School, Kalamazoo, Michigan ; Professor William J. Bray, First District Normal School, Kirksville, Missouri ; and Dr. Albert Leonard, Superintendent of Schools, New Rochelle, New .York ; each of whom read the manuscript in its original form. He is also indebted to Professors Clarence W. Greene and Frank W. Douglas, Albion College, and to Professor William H. Keeble, College of William and Mary, for valuable aid in the preparation of the chapters dealing with physical subjects, and to Dr. William C. Bagley, of Teachers College, Columbia University, for reading the discussion of the scientific method found in the opening chapters.

Contents

CHAPT^ PAGE

I. Science and the Scientific Method . . i

II. What the Young Scientist Must LEAim to Do 12

Chapter One Science And The Scientific Method

This is a book in elementary science, and the pupil who uses it is asked to be a scientist . This means that he must work as a scientist works ; think as a scientist thinks ; and in this way imd out for himself some of the things that other scientists have learoed. In order that he may begin his studies in the right way, he should know what science is and how a scientist goes about his work.

What science is. Science is defined as knowledge of any given subject properly arranged and classified. A person may know a great many facts about a given thing, but if his knowledge is not arranged according to some system or plan it cannot be called scientific knowledge. For example, an Indian may know the names of many of the plants that grow in the woods, when and where to look for them, how to compound medicines from them, and when their fruits will be ripe ; but he cannot be called a scientific botanist, partly because his knowledge is not extensive enough, but more particularly because it is not organized and because his ideas have not been verified by exact observation and experiment.^

The scientific habit. In using this book you will often be asked to make observations and experiments, and to arrange or tabulate in an orderly manner the facts that you collect, so that you may grow into what may be called the scientific habit . The most important thing that can be learned from a study of science is the method of thinking and working which the scientist uses, and you will be asked to do things in a scientific way in order that you may learn this method. Then you will be able to apply the method of science in all your work as long as you Uve.

The scientific method. By using the scientific method you can answer many of your own questions without the aid of a teacher. Sometimes you can find your answers by careful observation ; sometimes you will find them only by experiment. By one or the other of these two methods men of science have made all their inventions and discoveries, and through their use scientists

* Science is knowledge gained and verified by exact observation and correct thinking, especially as methodically formulated and arranged in a rational system. — Standard Dictionary, are every day asking questions of Nature and receiving their replies from her. The value of the scientific method lies in the fact that it enables us to gain new knowledge ; by its use we can get information for ourselves without the aid of teachers or the use of books.

Illustrations of the method. An understanding of the scientific method is so important that we shall give several illustrations of how it is used. Suppose, for example, that you see what looks like a load of wheat in bags, passing your house, and you wonder how heavy the load is. You observe that the bags are in three rows, with 8 bags in a row, and that there is an additional bag on top of the load. How many bags are there? You already know that bags of this kind hold 2 bushels. How many bushels are in the load? A bushel of wheat weighs 60 pounds. How many pounds in the load? A ton is 2000 pounds. How many tons in the load ?

When you have made your calculations, you have answered the question for yourself. By the use of your eyes and your mind , you have learned the weight of the load of wheat.

Steps in the process. In working out a problem like the above, your mind goes through four, and sometimes five,

Fio. 4. Tfae boys wonder what the Fio. 5. They make their observa-

tortoise weigha. tiona .

separate steps, all so woven into each other that they form one continuous story. These steps are as follows :

(i) Your attention is attracted to some unusual object or incident and you wonder what it is or what it is all about; you are curious to know ; your interest is aroused . Tliis is the first step in starting a train of thought in your mind, and the next step in the process ought to be a careful examination of that which has aroused your curiosity.

(2) You see certain things with your eyes, or you learn certain facts through your hearing or some other one of your senses . This step, which we call observation , is the most important step of all, because it forms the basis of what follows. What you are observing may be something that occurs about you in nature; but often it will be necessary to make an experiment and watch its progress, in order to get the facts you desire.

(3) You quickly recall what you already know about the thing you are now seeing or hearing. You have seen something Uke it before and you already know some facts about it. These facts are brought together and added to what you are now learning by observation. By this process your knowledge of the object is enlarged and enriched ; and a more thorough observation might furnish you with other facts that would add still more to your knowledge of the object.

(4) The fourth step is to come to some conclusion as a result of your study ; to form some hypothesis, or theory, that will explain what you have observed. The conclusion, or hypothesis, must be so definite that it can be caressed clearly. Notice that the more accurate your observations have been and the more you are able to add to them from previous experiences, the more definite and clearwill be the conclusion you are able to reach. (5) A fifth step must frequently be taken by the scientist. It may be called the step of verification . We are not always sure that the conclusion we reach is the exact truth, and we should stand ready to change our views when new facts or principles come to our knowledge.

Many times we may verify, or prove, the truth of our conclusions by further questions or experiments, and Fig. 8. 11^ v«^ their con- whenever it is possible this should be done.

To understand this method better, let us now write out all that passed through your mind as you studied the incident of the load of wheat. In order to help in keeping each step separate from the others, the second one is printed in ordinary type ; the third step — that part of the process in which you recall what you have previously learned — is inclosed in quotation marks ; and the fourth step, or conclusion, is in heavy-faced type. The complete scientific story would run something like this:

I see 3 rows of bags with 8 bags in each row and there is one extra bag on top of the others ; 3 times 8 bags is 24 bags and one more makes 25 bags. " It is probably wheat." " Each bag contains 2 bushels." There are 2 times 25, or 50, bushels in the load. '' A bushel of wheat weighs 60 pounds/' so the load weighs 50 times 60 pounds, or 3000 pounds. " 20(5o pounds make one ton/' hence there are 1| tons on the wagon.

If you had become interested in this incident and your mind were active, perhaps you would not stop at this point. It is possible that you would go to the market to find whether this was really a load of wheat or not, and what was its exact weight. In this way you would verify your conclusion and thus carry out the fifth step of the process. You would, perhaps, also ask the farmer how many acres of wheat he had raised and how many bushels per acre he had secured ; you would learn what it is worth a bushel and compute the value of the wheat per acre. Your mind would perhaps also turn to the niunber of acres of wheat raised in the United States each year, the average yield per acre, the total number of bushels in the crop, where the wheat will be marketed, and the uses that are made of it. If you are not interested in such mental exercises, perhaps you will ask yourself why you do not like to think.

Another illustration. Other illustrations may help to give a better understanding of the scientific method. I see a man on the street clad in a strange costume and become interested in him. His outer garment, " I can hardly call it a coat," is made of that peculiar kind of

Fio. (h cloth known as " plaid " ; I notice that his clothing comes only to his knees, and that his legs are bare from the knee down to the tops of his plaid stockings ; then, " I remember that such cloth and costume are worn in the northern part of Great Britain." I conclude that he must be a Scotchman. I observe that he carries a strange instrument and when he puts it to his mouth it gives out an unusual sound. " It is probably a musical instrument " ; it is a pair of bagpipes.

When I return home, I look up bagpipes in the dictionary and find a picture of a Scotch Highlander with an instrument like the one I saw on the street, I have tested my conclusion and found it correct.

A tJiird illustration. I go fishing ; presently I "get a bite " ; I feel something tugging away at my line. It must be a fish. I draw it out. " What a strange fish ! " It is long and slim and slippery ; it has no scales. It cannot be a common fish. I let it touch the ground and it quickly ties my line into knots. " I have heard a fisherman say that eels do this," " I remember a picture of an eel that I have seen." It is an eel.

Still other illustrations. I am traveling on the cars ; we pass through a city in which I see some very high buildings. " Tall buildings are found only in large cities." This is a large city. " I remember that Grand Rapids is one of the principal cities on the railroad running from my home to Chicago." This must be Grand Rapids. I now consult my time table to see when we are due at the Grand Rapids station and find that we should be there in two minutes. The brakeman tells me that the train is on time ; so I am sure that this city is Grand Rapids.

Two girls are expecting to go on a picnic. Early in the morning they scan the sky. Dark, threatening clouds are gathering in the east. " It is going to rain " ; we cannot go ! They continue to study the sky, and presently the clouds break away and the blue sky appears. '' It is clearing up " ; it will not rain after all and we can go.

Two boys are roaming the fields with their eyes wide open to see what they can find that is valuable or interesting. They find some bright, gUstening, yellow particles as a part of a rock. " It looks like gold. I wonder if it is gold." How shall we find out whether it is gold? " I've heard my father say that a mineral called fool's gold is almost as bright and as yellow as real gold."

They carry a piece of the rock to their teacher, and he takes them to the chemical laboratory. He tells them that what is called " fool's gold " is not gold at all, but a compound of iron and sulfur. We can tell what it is by an experiment. If it is pure gold it will not dissolve in hydrochloric acid ; if it is fool's gold it will dissolve in the acid and will give off a disagreeable odor which will remind one of decaying eggs. Pure gold is lo Science for Beginners

soft and can be whittled with a knife. Fool's gold is hard and generally separates from the rock in small, flat scales. The tests are made. The yellow mineral dissolves in the acid. It is fool's gold. By the scientific method the answer to the question has been found.

Two additional advantages of the scientific method. This is a much better method of getting knowledge than merely reading in a book, because we can understand and use better the knowledge we have worked out for ourselves, and also because by this method we learn to do our own seeing and thinking and thus become able to get information that is not to be found in books. That " thing knowledge is better than book knowledge " you will readily understand, and when you remember that the answers to the problems that meet us all through life are not written out in books, you will appreciate the importance of a method that will enable you to get for yourself the information you will need in solving these problems.

A clever scientist. Near the end of the season a boy announced the height of a tall tree to be 33 feet.

" Why, how do you know? " he was asked.

" Measured it."

"How?"

" Foot rule and yardstick."

" You didn't climb that tall tree? " his mother asked anxiously.

" No'm ; I just found the length of the shadow and measured that."

" But the length of the shadow changes."

Fjg. 10. Measuring tbj height of a tree.

" Yes'm ; but twice a day the shadows are just as long as the things themselves. I've been trying it all sununer. I drove a stick into the ground, and when its shadow was just as long as the stick, I knew that the shadow of the tree would be just as long as the tree, and that's 33 feet."

Chapter Two

The scientist collects his facts or principles, arranges them so that they will give an orderly view of the subject as a whole, and then draws his conclusions from them. Described in this way the method of the scientist seems simple ; but in reality it requires skill and care to collect facts and arrange them so that their meaning will be clear. It is very important, therefore, that the pupil who is just beginning his studies in science should understand what he must do to carry out the scientific method successfully. This subject we shall discuss in the present chapter, but it should be remembered that it is only by using the method that a real mastery of it will come to you. " Thing knowledge is better than book knowledge," whether it be in baseball, in arithmetic, or in the method that the scientist uses in his work.

The scientist must learn to observe. To observe is to take notice; to see; to give attention to what one sees and hears ; . to perceive ; to discover ; to learn. The scientist must observe because it is through observation that he collects his facts. Have you the ability to observe accurately? Can you see clearly and can you hear distinctly? Are all your senses wide awake and on the alert? In a word, are your powers of observation strong and active, and have you formed the habit of observation? A few tests will help you to answer some of these questions.

Exercise i. Let the teacher place a few articles on the table and cover them with a cloth or paper. Let the cover be removed for a minute and then let each pupil make a list of the articles. What wovild be your marking on the scale of a hundred in this test?

Exercise 2. Let the teacher remove some of the articles from the table and disarrange the others. Then let the pupils call for the objects that have been removed.

Exercise 3. If you Uve in the country, make from memory a Kst of the tools and machines left without proper shelter that you noticed on your way to school in the morning. Look again when you go home in the evening. Let different pupils do this and compare their hsts.

Exercise 4. Make an inventory, from memory, of the objects in some room at home, — the sitting room, for example. Take the inventory home and find out how many prominent objects you have omitted.

Exercise 5. Make from memory a picture of the face of the clock at home. What figure is at the top? Which is at the bottom? What kind of figures are used? Do the same for your watch if you have one. In each case verify your results.

The scientist must learn to measure. The first and most important step in all scientific work is to get the facts and get them right. By the use of rules, scales, and other measuring instnunents we can help our eyes and ears and other senses to make our observations much more exact. All our modem sciences, but especially physics, astronomy, chemistry, and mathematics, rest upon the ability of the scientist to make exact measurements. For linear measurements we use the inch, the foot, the centimeter, or the meter ; for areas, the square inch, square foot, square centimeter, or square meter; for cubic measurements, the cubic inch, cubic foot, cubic centimeter, or cubic meter. For measuring volume we use the liquid pint, quart, or gallon ; the dry pint, quart, or peck ; the liter and its subdivisions and multiples.

In the laboratories of our universities, scientists can measure the size of a disease germ that is only one fifty-thousandth of an inch in diameter ; they can weigh the ink that you use in writing your name. Fine measurements like these are, of course, far beyond your present power ; but if you wish to make true progress in even elementary science, you must become thoroughly acquainted with the units of measurement with which scientists work. The best way to become acquainted with these units is to use them, and a pocket rule is an excellent companion for the knife that is to be found in the pocket of alihost every boy.

Flo. II. Some tools tlut a young »ientist should leani to uae.

The young scientist must learn to record. Our' recollections of what we have seen and heard are too scattered and unreliable to allow us to dq>end, in our scientific work, on what we remember. A third thing, therefore, that the young scientist should learn to do is to keep a record. He should be able to use drawing instruments well enough to make a diagram or plan that will aptly illustrate his thoughts. He should become skillful in tabulating his knowledge, a process which will be fully explained and illustrated in this book.

It is a good plan always to have at hand a notebook into which anything of importance may be put. Keeping this book will afford many opportunities to practice and develop the power of recording, and it will cause as much mental growth as anything the pupil can do.

Classification necessary in science. Science is clashed knowledge, and learning to classify is an important part of a scientific training. Let us clearly imderstand what is meant by the term " classification," and also how a scientist must constantly use it in order to reduce his knowledge to a scientific form.

Two steps in the process of classification. Classification consists of two separate steps : (i) the choice of a proper basis for classification , and (2) the reference of the things to be classified to that basis.

For example, suppose we should take our stand at a favorable place upon some crowded city street, and make a classification of the people as they pass by, and suppose that we were to take sex as the basis of our classification. This would require us to refer each person either to the class male , or to the class female. In most cases this could easily be done, but in the case of some foreigners, with their queer costumes, there might be diflSiculty in making an accurate classification.

Or suppose our task were to classify them as men, women, boys, or girls. The difficulties would be somewhat greater than before, as it could not always be easily determined, in a given case, whether a person was really a boy or had passed the line between boyhood and manhood. If we were required to classify them as to height, the problem would require that every person be halted long enough to have his measure taken. If the basis of classification were nationality, and we desired to do the work very accurately, then every person would be required to give proof of the place of his birth. Suggest several other schemes that might be used in classifying people as they pass on the street, and in each case state what must be done to carry out the scheme.

A wise basis of classification important. It is very important that a correct basis of classification shall be chosen, or else useless work will be done. For example, a librarian wishes to classify a. collection of books so that they will be most useful to the readers who come to the library. He might classify them according to color, size, or the material from which the covers are made ; but such a classification would not be well chosen, for it ' is clear that on any of these bases books would be thrown together which are very far apart in their real character. What would be a better basis of classification? Why? Classiflcation of outdoor objects. Take your stand out of doors and make a list of 20 different objects that you see, such as trees, rocks, clouds, houses, fences, birds, shrubs, automobiles, forests, yards, and sidewalks. You will notice that some of these things have been produced by nature , and others have been made by man . This suggests a good basis of classification. Classify as natural or artificial the objects you have listed.

Using the same list of objects, notice that some things are alive. These things may be classified as plants or animals. What is the difiference between a plant and an animal? Give a good deal of careful thought to this question. What is the difference between a cow and a cabbage? How are they alike? Does a cow require food ? So does a cabbage. Does a cow grow by means of the food it consimies? So does the cabbage. Where does the cow get its food? Where does the cabbage get its food ?

Exercise 6. Make a list of 20 animals that you know. Make a list of 20 plants that you know. In what ways do the animals differ from the plants? In what ways are animals and plants alike?

The chronological order. Sometimes it is best to arrange facts or events in what is known as the chronolog - ical, or time, order ; i.e., the order in which the events occurred in time. For example, to mention the names of Washington, McKinley, and Lincoln would be to arrange them in a wrong order ; to speak of breakfast, supper, and dinner would be to place the words in a wrong order. Would it be proper to list them as supper, breakfast, and dinner?

Exercise 7. Mention the days of the week in chronological order ; the months of the year ; the presidents of the United States ; six events which lead up to a national election. Think of a half-dozen other lists of acts or events that can be arranged chronologically.

The alphabetical order. Another method of arrangement which is frequently used by the scientist is the alphabetical order. Sometimes this is the proper method, and again it may be unscientific to arrange material in this way. If the object is to arrange the matter in such a way that any item can be found quickly and easily, the alphabetical arrangement is the proper one. Thus a book is almost worthless for reference unless it has an alphabetical index; a dictionary that did not have this arrangement could not be used; a list of voters in a township should always be made in this way. The items on a Ust which is so made may be alphabetical only as far as their initial letters are concemed; but it is better -to make the list strictly alphabetical as to all the letters.

Exercise 8. Arrange alphabetically the names of the pupils in your class ; the months of the year ; the presidents of the United States ; the states of the Union ; the oflScers of your state ; a dozen occupations followed by the people in your town. Make at least six other alphabetical lists.

Tabulating facts. Many times the scientist finds that the meaning of his facts becomes clearer and that they are more easily remembered if they are tabulated ; i.e., arranged in tables. These tables take whatever form the scientist may choose, and it is an excellent exercise for a pupil to use his ingenuity in inventing methods of representing a given series of facts. You will have many opportimities to do this as you pursue the work outlined in this book.