Always see it in English

Create your own homemade motor with the scientist Javier Santaolalla

Would you believe us if we told you that you can build your own motor at home?

We have here as a guest today the scientific communicator Javier Santaolalla, who is going to share some fun secrets about electricity with us. He will show us:

How to make a simple homopolar motor at home. Are you up for it?

It is hard to imagine that more than 2,000 years ago we were already studying and thinking about how electricity works. In fact, the term "electricity" comes from the Greek word elektros or "amber", a stone that produced very curious effects when rubbed (it can become electrically charged by contact and separation after friction with a material such as wool). An astonishing fact that did not escape notice by the philosophers in ancient Greece—the grandparents of today's physicists.

That same spirit of curiosity was the driving force that lead Gilbert, Oersted, Ampere, Faraday and Maxwell to take an interest in electricity some 1,500 years later.

During the Enlightenment a new way of understanding the world had developed, that of hypothesis and experimentation. This is what we now call the scientific method, combined with the powerful tool of mathematics. And these sages set their eyes and their minds on electricity and magnetism.

Three centuries later it is difficult for us to understand that this work with such a theoretical spirit was the foundation of one of the greatest revolutions in the history of Humanity: a few scientists with grand ideas brought light to the darkness.

But electricity does not only mean "light", it also means movement. Electricity has powered us, paving the way for large industries and, above all, for worldwide interconnections and the era of communications. We can now enjoy all of this thanks to the minds of a few geniuses.

“But electricity does not only mean "light", it also means movement”

Faraday, electric generators and electric motors

Faraday was a young Englishman with no formal studies but with great experimental talent. He bridged theory and practice, discovering the electric generator, a machine that produces electricity from movement.

And also its counterpart, the electric motor: a device that does the reverse conversion, from electricity to motion. It seems hard to believe, but indeed, the basis of our modern technological and industrial society, even communications and information, all comes from a concept as simple as the following:


The circulation of electrons and the conversion of mechanical movement into electricity, and vice versa.

Let's think about this a little. Let's consider it in a daily setting:

Every day we press switches at home dozens of times and - we get electricity!

We also turn on the washing machine, the coffee maker or the television, with a single click, a simple switch, immediately and with no effort.

It sounds like magic, but it isn't. More than two centuries of inventions, developments and great minds have made this possible. The most wonderful and surprising thing about it is that it is conceptually very simple!

Faraday observed that a magnet rotating inside a cable produces electricity, which is known as electromagnetic induction, or Faraday's law.

The reverse phenomenon had already been observed, whereby the movement of current in a circuit produces magnetism, i.e. the circuit becomes a "magnet". Now take this as a law. Why does this happen? Nature works like this. These are the rules of the Universe.

Let's think of something that moves, water in a river, for example.

There is perpetual movement, the water in the river never stops. Actually, there are many sources of energy, but perhaps the most important of these is the Sun.

Well, let's think of it like this: the water in the river moves, so here we have our energy source. Let's make the water from this river move something, a wheel, for example. OK. If we connect a magnet to that wheel and put it inside a circuit, the magnet rotates due to the movement of the river-driven wheel and induces a current in the circuit. Bravo!

Let's take that electricity and transport it through wires to a human hub, a city. Let's make the electricity go through a circuit with a magnet inside it. The magnet will be affected by the current and begin to rotate. This is the reverse process, which is the electric motor. Do you see what's going on? We have transferred the energy from the movement of the river, we have transmitted it and we have transformed it into the movement of a food processor, a washing machine, a car. Movement to movement, with electricity as the intermediary. Look around. How much of what you see is moving in this way? Isn't it just wonderful, amazing? Even more so when you can yourself be a direct witness of this revolutionary "magic". Are you up for it?

How to make a homopolar motor at home

Today we are going to create the simplest motor that can be created: a homopolar motor. It works like a motor, using the same principles explained above and in such a simple way that you can make one at home, from basic (and cheap) things.

“A homopolar motor works using the same principles in a simple way. You can make one at home from basic and cheap things”

The process is very simple, I show you how to do it in this video, which you can also see in the Stories on the Endesa Instagram profile.

All you have to remember is that the movement of electrons in a magnetic field produces circular motion. Well let's get down to it.

We need moving electrons. Easy! We can use a battery! If we take a battery and close the circuit with a cable, we will have electron transit. Perfect!

Now we need those electrons to move within a magnetic field. A magnetic field? That sounds familiar! Yes, magnets produce magnetic fields. Take a small neodymium disc magnet. and you will have your magnetic field source.

If we place the battery with the cable closing the circuit on top of the magnet, we will have what we were looking for: a flow of electrons within a magnetic field. We have our circular movement, our own motor. Try it, admire it and be amazed.

It seems incredible that such a simple concept moves the world, but that's how it is.

Greek sages wondered about the origin of this mysterious force some 2,000 years ago. Today we use it for practically everything and we can't imagine a world without it. A silent, invisible force that powers the world, we call it

electricity, and It Isn't Magic, It's Energy.

Who is Javier Santaolalla?

Javier Santaolalla is a particle physicist and telecommunications engineer. He worked at CERN and CNES. His current work focuses on scientific communication through publishing, activity on social networks, collaboration in the media and participation in shows.

Javier Santaolalla has participated in our initiative It Isn't Magic, It's Energy and helps us understand the keys that allow us to carry out small home experiments applying the scientific principles that govern energy.

Don't miss the rest of our experiments, enjoy them in the Stories of our Instagram profile.

Follow us, share your version of our experiments with us and you can win an electric bicycle. Go ahead and participate!

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