Electricity for Boys

Electricity for Boys.

by J. S. Zerbe.

INTRODUCTORY

Electricity, like every science, presents two phases to the student, one belonging to a theoretical knowledge, and the other which pertains to the practical application of that knowledge. The boy is directly interested in the practical use which he can make of this wonderful phenomenon in nature.

It is, in reality, the most successful avenue by which he may obtain the theory, for he learns the abstract more readily from concrete examples.

It is an art in which shop practice is a greater educator than can be possible with books. Boys are not, generally, inclined to speculate or theorize on phenomena apart from the work itself; but once put them into contact with the mechanism itself, let them become a living part of it, and they will commence to reason and think for themselves.

It would be a dry, dull and uninteresting thing to tell a boy that electricity can be generated by riveting together two pieces of dissimilar metals, and applying heat to the juncture. But put into his hands the metals, and set him to perform the actual work of riveting the metals together, then wiring up the ends of the metals, heating them, and, with a galvanometer, watching for results, it will at once make him see something in the experiment which never occurred when the abstract theory was propounded.

He will inquire first what metals should be used to get the best results, and finally, he will speculate as to the reasons for the phenomena. When he learns that all metals are positive-negative or negative-positive to each other, he has grasped a new idea in the realm of knowledge, which he unconsciously traces back still further, only to learn that he has entered a field which relates to the const.i.tution of matter itself. As he follows the subject through its various channels he will learn that there is a common source of all things; a manifestation common to all matter, and that all substances in nature are linked together in a most wonderful way.

An impulse must be given to a boy's training. The time is past for the rule-and-rote method. The rule can be learned better by a manual application than by committing a sentence to memory.

In the preparation of this book, therefore, I have made practice and work the predominating factors. It has been my aim to suggest the best form in which to do the things in a practical way, and from that work, as the boy carries it out, to deduce certain laws and develop the principles which underlie them. Wherever it is deemed possible to do so, it is planned to have the boy make these discoveries for himself, so as to encourage him to become a thinker and a reasoner instead of a mere machine.

A boy does not develop into a philosopher or a scientist through being told he must learn the principles of this teaching, or the fundamentals of that school of reasoning. He will unconsciously imbibe the spirit and the willingness if we but place before him the tools by which he may build even the simple machinery that displays the various electrical manifestations.

CHAPTER I

THE STUDY OF ELECTRICITY. HISTORICAL

There is no study so profound as electricity. It is a marvel to the scientist as well as to the novice. It is simple in its manifestations, but most complex in its organization and in its ramifications. It has been shown that light, heat, magnetism and electricity are the same, but that they differ merely in their modes of motion.

FIRST HISTORICAL ACCOUNT.--The first historical account of electricity dates back to 600 years B. C. Thales of Miletus was the first to describe the properties of amber, which, when rubbed, attracted and repelled light bodies. The ancients also described what was probably tourmaline, a mineral which has the same qualities. The torpedo, a fish which has the power of emitting electric impulses, was known in very early times.

From that period down to about the year 1600 no accounts of any historical value have been given. Dr. Gilbert, of England, made a number of researches at that time, princ.i.p.ally with amber and other materials, and Boyle, in 1650, made numerous experiments with frictional electricity.

Sir Isaac Newton also took up the subject at about the same period. In 1705 Hawksbee made numerous experiments; also Gray, in 1720, and a Welshman, Dufay, at about the same time. The Germans, from 1740 to 1780, made many experiments. In 1740, at Leyden, was discovered the jar which bears that name. Before that time, all experiments began and ended with frictional electricity.

The first attempt to "bottle" electricity was attempted by Muschenbr[oe]ck, at Leyden, who conceived the idea that electricity in materials might be retained by surrounding them with bodies which did not conduct the current. He electrified some water in a jar, and communication having been established between the water and the prime conductor, his a.s.sistant, who was holding the bottle, on trying to disengage the communicating wire, received a sudden shock.

In 1747 Sir William Watson fired gunpowder by an electric spark, and, later on, a party from the Royal Society, in conjunction with Watson, conducted a series of experiments to determine the velocity of the electric fluid, as it was then termed.

Benjamin Franklin, in 1750, showed that lightning was electricity, and later on made his interesting experiments with the kite and the key.

DISCOVERING GALVANIC ELECTRICITY.--The great discovery of Galvani, in 1790, led to the recognition of a new element in electricity, called galvanic or voltaic (named after the experimenter, Volta), and now known to be identical with frictional electricity. In 1805 Poisson was the first to a.n.a.lyze electricity; and when [OE]rsted of Copenhagen, in 1820, discovered the magnetic action of electricity, it offered a great stimulus to the science, and paved the way for investigation in a new direction. Ampere was the first to develop the idea that a motor or a dynamo could be made operative by means of the electro-magnetic current; and Faraday, about 1830, discovered electro-magnetic rotation.

ELECTRO-MAGNETIC FORCE.--From this time on the knowledge of electricity grew with amazing rapidity. Ohm's definition of electro-motive force, current strength and resistance eventuated into Ohm's law. Thomson greatly simplified the galvanometer, and Wheatstone invented the rheostat, a means of measuring resistance, about 1850. Then primary batteries were brought forward by Daniels, Grove, Bunsen and Thomson, and electrolysis by Faraday. Then came the instruments of precision--the electrometer, the resistance bridge, the ammeter, the voltmeter--all of the utmost value in the science.

MEASURING INSTRUMENTS.--The perfection of measuring instruments did more to advance electricity than almost any other field of endeavor; so that after 1875 the inventors took up the subject, and by their energy developed and put into practical operation a most wonderful array of mechanism, which has become valuable in the service of man in almost every field of human activity.

RAPIDITY OF MODERN PROGRESS.--This brief history is given merely to show what wonders have been accomplished in a few years. The art is really less than fifty years old, and yet so rapidly has it gone forward that it is not at all surprising to hear the remark, that the end of the wonders has been reached. Less than twenty-five years ago a high official of the United States Patent Office stated that it was probable the end of electrical research had been reached. The most wonderful developments have been made since that time; and now, as in the past, one discovery is but the prelude to another still more remarkable. We are beginning to learn that we are only on the threshold of that storehouse in which nature has locked her secrets, and that there is no limit to human ingenuity.

HOW TO ACQUIRE THE VAST KNOWLEDGE.--As the boy, with his limited vision, surveys this vast acc.u.mulation of tools, instruments and machinery, and sees what has been and is now being accomplished, it is not to be wondered at that he should enter the field with timidity. In his mind the great question is, how to acquire the knowledge. There is so much to learn. How can it be accomplished?

The answer to this is, that the student of to-day has the advantage of the knowledge of all who have gone before; and now the pertinent thing is to acquire that knowledge.

THE MEANS EMPLOYED.--This brings us definitely down to an examination of the means that we shall employ to instil this knowledge, so that it may become a permanent a.s.set to the student's store of information.

The most significant thing in the history of electrical development is the knowledge that of all the great scientists not one of them ever added any knowledge to the science on purely speculative reasoning. All of them were experimenters. They practically applied and developed their theories in the laboratory or the workshop. The natural inference is, therefore, that the boy who starts out to acquire a knowledge of electricity, must not only theorize, but that he shall, primarily, conduct the experiments, and thereby acquire the information in a practical way, one example of which will make a more lasting impression than pages of dry text.

Throughout these pages, therefore, I shall, as briefly as possible, point out the theories involved, as a foundation for the work, and then ill.u.s.trate the structural types or samples; and the work is so arranged that what is done to-day is merely a prelude or stepping-stone to the next phase of the art. In reality, we shall travel, to a considerable extent, the course which the great investigators followed when they were groping for the facts and discovering the great manifestations in nature.

CHAPTER II

WHAT TOOLS AND APPARATUS ARE NEEDED

PREPARING THE WORKSHOP.--Before commencing actual experiments we should prepare the workshop and tools. Since we are going into this work as pioneers, we shall have to be dependent upon our own efforts for the production of the electrical apparatus, so as to be able, with our home-made factory, to provide the power, the heat and the electricity.

Then, finding we are successful in these enterprises, we may look forward for "more worlds to conquer."

By this time our neighbors will become interested in and solicit work from us.

USES OF OUR WORKSHOPS.--They may want us to test batteries, and it then becomes necessary to construct mechanism to detect and measure electricity; to install new and improved apparatus; and to put in and connect up electric bells in their houses, as well as burglar alarms. To meet the requirements, we put in a telegraph line, having learned, as well as we are able, how they are made and operated. But we find the telegraph too slow and altogether unsuited for our purposes, as well as for the uses of the neighborhood, so we conclude to put in a telephone system.

WHAT TO BUILD.--It is necessary, therefore, to commence right at the bottom to build a telephone, a transmitter, a receiver and a switch-board for our system. From the telephone we soon see the desirability of getting into touch with the great outside world, and wireless telegraphy absorbs our time and energies.

But as we learn more and more of the wonderful things electricity will do, we are brought into contact with problems which directly interest the home. Sanitation attracts our attention. Why cannot electricity act as an agent to purify our drinking water, to sterilize sewage and to arrest offensive odors? We must, therefore, learn something about the subject of electrolysis.

WHAT TO LEARN.--The decomposition of water is not the only thing that we shall describe pertaining to this subject. We go a step further, and find that we can decompose metals as well as liquids, and that we can make a pure metal out of an impure one, as well as make the foulest water pure. But we shall also, in the course of our experiments, find that a cheap metal can be coated with a costly one by means of electricity--that we can electroplate by electrolysis.

USES OF THE ELECTRICAL DEVICES.--While all this is progressing and our factory is turning out an amazing variety of useful articles, we are led to inquire into the uses to which we may devote our surplus electricity.

The current may be diverted for boiling water; for welding metals; for heating sad-irons, as well as for other purposes which are daily required.

TOOLS.--To do these things tools are necessary, and for the present they should not be expensive. A small, rigidly built bench is the first requirement. This may be made, as shown in Fig. 1, of three 2-inch planks, each 10 inches wide and 6 feet long, mounted on legs 36 inches in height. In the front part are three drawers for your material, or the small odds and ends, as well as for such little tools as you may acc.u.mulate. Then you will need a small vise, say, with a 2-inch jaw, and you will also require a hand reel for winding magnets. This will be fully described hereafter.

You can also, probably, get a small, cheap anvil, which will be of the greatest service in your work. It should be mounted close up to the work bench. Two small hammers, one with an A-shaped peon, and the other with a round peon, should be selected, and also a plane and a small wood saw with fine teeth. A bit stock, or a ratchet drill, if you can afford it, with a variety of small drills; two wood chisels, say of 3/8-inch and 3/4-inch widths; small cold chisels; hack saw, 10-inch blade; small iron square; pair of dividers; tin shears; wire cutters; 2 pairs of pliers, one flat and the other round-nosed; 2 awls, centering punch, wire cutters, and, finally, soldering tools.

[Ill.u.s.tration: _Fig. 2. Top View_ MAGNET-WINDING REEL]

[Ill.u.s.tration: _Fig. 3. Side View_ MAGNET-WINDING REEL]

If a gas stove is not available, a brazing torch is an essential tool.

Numerous small torches are being made, which are cheap and easily operated. A small soldering iron, with pointed end, should be provided; also metal shears and a small square; an awl and several sizes of gimlets; a screwdriver; pair of pliers and wire cutters.

From the foregoing it will be seen that the cost of tools is not a very expensive item.