Autobiography of an Electron — 12 - Our Heaviest Duties

Here the electron explains its behaviour in a dynamo at work.

The principle of the dynamo was discovered by Faraday in the thirties of last century.

He found that when a coil of wire was moved through a magnetic field, there was a current of electricity induced in the moving coil.

Experimental machines were constructed, and after a while a practical dynamo was evolved.

Wires are attached to a dynamo and the electric current is led out.

This current may be conducted to a distant tramway car, and, by sending the current through an electric motor, mechanical motion is produced and the car propelled along.

An electric motor is practically the same as a dynamo, but instead of turning its coil round in order to produce an electric current, we pass a current into the coil and it moves round.

It will be sufficient to leave the electron to tell its own story.

CHAPTER XII OUR HEAVIEST DUTIES

This is another of those roving commissions in which I have been privileged to take part on more than one occasion.

If you think of the giant size of an electric tramway car or a railway train, and try to compare one of these with an electron, such as your humble servant, it will seem quite ridiculous that I should suggest that it is we electrons who move those huge vehicles.

Yet such is the actual case.

Of course we require the application of very considerable power to urge us to so heavy a task.

All the energy which we can get from a few electric batteries might enable us to drive a toy car, but when it comes to turning the wheels of a real car or train, we require a correspondingly greater amount of energy.

I may as well tell you quite frankly that we electrons are only the intermediaries or go-betweens.

Indeed, you must have noticed that in every case we act merely as a connecting link between matter and the aether, and between the aether and matter.

But what I want to tell you of, is the part we play in moving an electric car or railway train.

It is really all very simple if you could only see it from our standpoint.

Picture a host of us attached to copper atoms in a coil of wire which is being moved through that disturbed aether called a _magnetic field_.

We are set in motion immediately.

It is true that when we are moved forward into the field we march off in one direction, only to be arrested and made to move off in the opposite direction as we leave the field, but it really makes no difference in our working capabilities as long as we are kept on the move.

This is what is actually taking place in the armature of a dynamo as it revolves between the poles of the electro-magnet.

There is no peace for us so long as the coil is kept revolving; we are kept in a constant state of rapid to-and-fro motion.

[Illustration: A TRAIN IMPELLED BY MOVING ELECTRONS _By permission of Siemens Schuckert Werke_ _Berlin_ It is remarkable that the motion of electrons in an electric conductor can result in the movement of heavy vehicles.

How this comes about is explained in Chapter XII.

] This is all we electrons do in a dynamo, but when the ends of the outer circuit or mains are brought into contact with the ends of our revolving coil, we set the electrons in the mains surging to and fro in step with ourselves.

Man describes this motion of the electrons in the mains as an _alternating electric current_, but by a simple commutator on the dynamo he may arrange that we set the electrons marching in one direction in the mains.

This he describes as a _direct electric current_.

It is a matter of indifference to us whether man drives our coil round by means of a steam-engine, a water-wheel, or a wind-mill; all that we electrons want is to be kept surging or vibrating to and fro.

Now you will be able to appreciate how we electrons get up sufficient motion to enable us to perform what I have described as _our heaviest duties_.

Perhaps you will find it difficult to believe me when I tell you that as we march along the connecting wire to a distant tramway car we transmit the energy through the surrounding aether, and not through the wire.

This is our mode of working in every case, whether it be an electric bell, a telegraph, or telephone.

That is to say, while we electrons move from atom to atom in the connecting wire, it is the disturbed aether surrounding us which transmits the energy.

You must have realised by this time how very intimate is the relationship between ourselves and the aether.

To return to the tale of our tramway work, you will picture my fellow-electrons aboard the car being energised by the incoming current.

Those electrons present in the armature coil of the motor are set into motion, as also are those in the wire of the neighbouring electro-magnet.

The result is that these two sets of electrons so disturb the aether and affect one another that the coil is moved round into a different position.

You will remember the experiment of which I told you, in which a magnetic needle would insist always in taking up a position at right angles to a wire in which an electric current is passing.

Well, when the motor coil has turned into its new position, we electrons receive an impulse from our friends in the line-wire which causes us to retrace our steps in the coil.

This action of ours causes the coil to make a further movement in the same direction as at first.

Again we change our direction of march, and again the coil changes its position towards the electro-magnet.

The sole duty of these electrons in the armature coil is to keep surging to and fro, while those electrons in the electro-magnet keep up a steady march in one direction.

This arrangement necessitates the armature coil to keep changing its position continually, and when we have the armature coil spinning round at a steady pace, it is easy for man to connect the armature to the axles of the tramway car and cause us to drive the wheels round.

I need hardly say that it makes no difference to us whether we are asked to drive a tramway car, a railway train, or a host of machines in a factory or workshop.

All that we electrons in the motor require is to have sufficient energy passed along to us from our fellows in the distant dynamo.

Again I admit frankly that the atoms of matter play a very important part in these our heaviest duties, but you will see that without our active assistance they could not transmit the necessary energy to a distant car or train.

CHAPTER XIII A BOON TO MAN