Discovery of Electricity
The electric charge
Luigi Galvani and Alessandro Volta
Magnetism
Hans Christian Oerstedt
Andre Marie Ampere
Michael Faraday und die Elektrodynamik

The Discovery of Electricity

Without electricity, we would probably still communicate today by physically transporting information back and forth on foot, horseback or boat. Even if we took the train or an airplane, it would still be a physical transport of messages. Attempts were made in the late 18th and early 19th centuries to send messages over long distances by transmitting optical signals from a series of towers. This type of message transmission was expensive, cumbersome and a so called „fair-weather technology“, that only functioned during the day time with good visibility.

The electricity became a game changer.

Today it is difficult to imagine a world without electricity. Our entire life is now determined, if not entirely dependent, on electricity. It is hard to believe that at the beginning of the 19th century nobody had any idea about ​this technology. Electrical phenomena have always been there in form of lightnings. However, these were so mysterious to people that they would only be attributed to Gods. In the Greek Culture was Zeuss and in the ancient German Culture was Thor.

The Greeks already described another electrical phenomenon observed in connection with rare stones. These stones came from the Baltic Sea a land where barbarians lived. The Greeks called these stones „electron“, we call them today amber. If these stones are rubbed with a cloth or fur, they acquired strange properties, they attract for example small particles. The reason remains however, a mystery. The amber „electron“ gave electricity its name.

The electric charge

Time passed by. The Romans were not interested in studying lightning and the properties of amber, nor did the Middle Ages bring any progress. Europe and the Orient, despite advanced science knowledge, did not come much further. Only the enlightenment in modern times finally led to questioning the „divine“ for the explanation of electrical events. Many scholars began to deal more intensively with the properties of matter and specially amber and its strange „electrical“ power. This property was called „charge“ and very soon they learned how to amplify and store charges.

In 1733 they started differentiating between two types charges, positive and negative charges. Positive charges attracted negative charges, while similar charges repelled each other. In 1774 a Dutch physicist from Leiden, Pieter van Musschenbroek, invented a device to store charges. This early form of a capacitor was called the Leiden Bottle.

There was however no explanation where these charges and their emanating power came from, nor their possible benefit.The electrical phenomena were only used for the entertainment of the audience. Everybody knows the effect when you charge a person with electricity and his hair stands on end

Luigi Galvani and Alessandro Volta

Many scholars experimented with electricity. One of them, the Italian Luigi Galvani, made an accidental discovery in 1780. He touched a dissected frog with a charged wire. To his astonishment, the frog’s thighs twitched. Galvani believed that animals had their own kind of electricity. This resulted in a separate research, which was called galvanism. All kind of sick experiments were carried out on living beings. They even didn’t hesitate from examining the human heads of guillotined victims. In fact, twitching of facial muscles could still be produced here by electricity.

It was frightening for people at that time that you could bring a dead organism to „life“ with galvanism. A young female author named Mary Shelley was inspired by the galvanic experiments to write a novel in 1818. In her novel a monster is created from human body parts and brought to life by electricity. She called the creator of this monster Frankenstein.

Alessandro Volta, another Italian researcher, considered „animal electricity“ to be a mistake. He postulated that electricity is produced by certain chemical processes. He invented the voltaic pile around 1800, the first usable battery. It created a power source from metals and certain liquids (electrolytes) with which cardboard was soaked. This was a gigantic progress. Until then, it was only possible to generate charge through friction, and „store“ it in so-called Leidner bottles. However, it discharged very quickly (e.g. by a spark) and had to be recharged. With a voltaic pile it was possible to generate a current of charges that could flow, e.g. through wires. There was a certain tragedy involved in Voltas discovery. This pillar was practically useless. There was no need for electricity. There was no engine, no lightbulb that could require this battery. You could only do small experiments and create sparks. Volta never saw the use of electricity and it was only after his death that the significance and usage of his invention became clear.

Magnetism

Magnetism was another mysterious phenomenon besides electricity. Since ancient Europe and China it was known, that some Iron ores, attracted themselves and iron. In addition, it was found that small needles of this iron oriented in a north-south direction. While this was interesting, it was of little use until around the year 1000, when this phenomenon began to be used for navigation, as a compass. This compass improved over time from a floating compass to a needle compass. This instrument became indispensable for navigation, which promoted high-sea shipping, especially in the 16th century.

A magnet was useful but puzzling and it definitely seemed to have nothing to do with electricity.

HANS CHRISTIAN OERSTEDT

Curiously, few people know a researcher named Oerstedt. However, many know Hans Christian Andersen, the great Danish storyteller. This was a close friend of Hans Christian Oerstedt. He was a sponsor of Andersen and helped him publish his famous fairy tales. So we owe him, among other things, „the little mermaid“. But this is just a side story of his life.

He was a physicist who explored all sorts of subjects in the early 19th century, including galvanism and electrostatics. He owned one of the new types of batteries originally invented by Volta and used it to experiment in his physics classes.

During Mr. Oerstedt’s lectures there happened to be many items on his table where he conducted experiments. By accident, a needle compass was located near the wire on which Oerstedt was demonstrating experiments with a current of charges coming from a battery. What happened next is comparable to Columbus‘ discovery of America.

Two different disciplines, magnetism and galvanism are related!

As Oerstedt let a current flow, the compass needle moved. An accident? Did someone bump into the table? Oerstedt repeated the experiment. Whenever he let the current flow, the needle deflects. It’s not a big deal from today’s perspective, but for a scholar of the early 19th century it was outrageous. Two completely different disciplines, galvanism (electricity) and magnetism were related to each other. Oerstedt was aware of this enormous discovery. He wrote a four-page article in Latin and published it throughout Europe. A new gate for electricity had been opened. The interaction of electricity and magnetism.

ANDRE-MARIE AMPERE

One of the researchers, who read Oerstedt’s article, was immediately aware of the implications of this discovery. His name was Andre-Marie Ampere. He repeated the experiment with the compass needle and realized that the movement of the needle came from the current-carrying wire and was also still influenced by the earth’s magnetic field. By eliminating this influence, he was able to determine that the magnetic needle was always aligned perpendicular to the current-carrying conductor. He assumed that the (charge) current created a magnetic field. In this case, current-carrying conductors should also exert force on themselves, just as magnets do.

He actually was able to show that current-carrying wires repel each other when the current flows in different directions and that they attract each other when it flows in the same direction. In any case, it was clear that currents could produce magnetic forces. This was a fact that would lead to many applications in the future. Ampere first used them to build a measuring instrument that he called a galvanometer. Compared to today’s instruments, it was very simple and very sensitive. It worked with magnetic needles attached to a mirror. It was possible to move a beam of light with the mirror, which made the smallest movements of the compass needle visible. Deflecting the compass needle by electricity, allowed to measure the current.

A new instrument would now allow to research „current“ of charges.

Michael Faraday and Electrodynamics

The first connections between electricity and magnetism had been found. A current creates a magnetic field. It was quickly discovered that this magnetic field could be generated specifically with coils. The magnetic field could be enforced by increasing the number of windings in the coil. This is how electromagnets were created which could be switched on and off by the current.

Michael Faraday, an English physicist, experimented with such coils in 1831. He created an arrangement with two coils around a ring-shaped iron core. He passed current through one coil and observed the effect on the other coil connected to a galvanometer with a magnetic needle. According to Oerstedt/Ampere, the needle should move when current is flowing.

This experiment failed. While current flowed permanently through one coil, no current could be detected through the second coil. However, each time the power was turned on or off, the compass needle deflected, and it deflected in different directions. Faraday concluded that a current was „induced“ when the magnetic field in the iron core builds up or decays, or simply „changes“.

Mechanical force can generate electricity and that electricity generates mechanical force. This discovery created a new discipline called electrical engineering and started the second industrial revolution.

Shortly after this initial experiment, Faraday made the following attempt: He pushed a bar magnet in and out of a coil, generating two power surges. The revolutionary aspect of this experiment was the possibility to generate electricity using a mechanical force. A new way to create current and electricity other than through the battery had been found. This was the discovery of electrodynamics, which would now completely change the world and ultimately started the second industrial revolution.