How Faraday Made Electricity with Magnets: Discovery of Induction, the Generator, & Magnetic Fields

How did Michael Faraday make electricity with magnets? And hey, how does anyone make electricity with magnets? And what does that have to do with the creation of the idea of magnetic fields? Well, watch this video and find out. Ready? Let's go. ♪ Electricity, electricity ♪ In 1826, an English scientist named Michael Faraday read that another Englishman named William Sturgeon had made a pretty strong magnet by wrapping wire around an iron bar and putting current in the wire. Because electricity makes the bar act like a magnet, Sturgeon's creation is logically called an electromagnet. Sturgeon had used an iron bar that was covered in lacquer and bare wire. Because of this, he had to be careful that the wires didn't touch, or the electricity would just short circuit across the wires instead of through them. Faraday had a little six-inch iron ring that wasn't coated. He decided to wrap the wires with cloth to insulate them instead of coating the iron ring. In this way, he could wrap the wires very closely together and make a much stronger electromagnet. Because this iron was a ring, Faraday wrapped two separate coils, one for the left side of the ring and one for the right. It looks like a strange artifact from a mummy's crypt. Faraday used to keep this ring in his pocket while he did other research. He was sure it would be useful somehow. He just didn't know how. Then in August of 1831, he took a professional risk. Faraday quit his government research job that he hated and decided to branch out on his own. What Faraday wanted to do was study electricity and magnetism. Specifically, he was determined to create electricity with a magnet. After all, it had been 11 years since a Danish man named Hans Christian Ørsted had shown that electricity pushes magnets. It seemed logical that magnets must affect electricity. For many years, Faraday had been tinkering with magnets and electricity, but to no avail. He wondered if the magnet wasn't strong enough. For that reason, Faraday took out his little ring from his pocket. He decided to use one side of the ring as his magnet and the other side as his tester to see if he could create current without directly connecting to a battery. He put a compass under the tester wire to see if it had any current. When Faraday connected a battery to the first coil, an amazing thing happened. The magnet next to the second coil twitched, then nothing. When he cut off the current, the magnet twitched again in the other direction, then nothing again. Faraday repeated this experiment many times and he found he created current in the second coil when the first one was charging up or discharging, but never when it was flowing steadily, even when it had incredibly large current. In other words, an electromagnet only creates current in another coil when the magnetic field was changing. If its strength is steady, nothing happens. Faraday wrote to a friend about his experiment. Quote, I'm busy just now, again on electromagnetism, and I think I've got hold of a good thing, but I can't say. It may be a weed instead of a fish that after all my labor, I may at last pull up. Faraday had managed to create electricity with electricity, but he still hadn't managed to create electricity with a magnet. After several attempts that were too subtle to be observed, Faraday pushed a very strong magnet into a coil of wire and retrieved it again. When the magnet was moving, the compass moved too. Here was the fish that Faraday was hoping to catch. He had briefly created electricity with magnets. He had another device at his disposal. The Royal Institution where Faraday worked had a giant magnet, actually 437 magnets stuck together that Faraday could play with. Faraday placed an iron bar on this great magnet, thereby making the iron bar a magnet too. When he moved the coil towards and away from the bar, it created current in the coil. However, even with this very strong magnet, no current was detected when the coil was still. Let's review Faraday's discovery. He created current in a wire if he moved the coil towards or away from a strong magnet, if he moved a magnet towards or away from a coil of wire, or if he increased or decreased the magnetism of an electromagnet near a coil of wire. Faraday needed a way to describe this new phenomenon. He was a visual thinker with no math skills, so he began imagining magnetic curves emanating from bar magnets, current-carrying wires, and electromagnets. For centuries, people had noticed that if you sprinkle iron filings around a bar magnet, it creates patterns. Faraday said that the iron filings were lining up with these, quote, lines of magnetic forces that were always present around the magnets and around current-carrying wire. The iron filings just made them visible. In this way, Faraday came up with the idea of magnetic fields way back in 1831. Faraday said that current was created or induced when the lines of magnetic force were broken or cut by the coil of wire. Think about pushing the bar magnet into a coil of wire. As you push the magnet, the magnetic field lines pass through the coil and induce current. Faraday felt it was this disturbance of the force, not to get too Star Wars about it, that created the current in the coil. Strangely enough, that is the theory we believe today. Faraday realized that the current he produced was in spurts. He wondered if he could make continuous current like a battery does. In this quest, he was helped by something called Arago's disc. See, nine years earlier, a swashbuckling Frenchman named Francois Arago had noticed that if a copper disc was rotated near a compass magnet, the compass magnet would turn too. Faraday decided that Arago's disc worked because moving the wheel moved parts of the wheel closer and further from the magnet, which induced current in the wheel. That induced current created a magnetic field that pushed the original magnet. Faraday decided to test his hypothesis with the giant magnet at his disposal. He added metal to his large magnet to make it into a U-shaped magnet. He then placed the copper disc so that it could spin between the poles and connected the disc with wires to a meter to measure the current. When he spun the wheel, the needle turned and stayed constant. Faraday had used motion to get constant current. In fact, he had invented the first electric generator. The scientific community was very impressed with his findings, and especially with his solution to the mystery of Arago's disc. Faraday himself felt particularly satisfied to have succeeded without using math, a subject he didn't know. Faraday published his work in 1832. It was so popular that the prime minister of England dropped by to see Faraday's generator firsthand. When the prime minister asked Faraday about its uses, Faraday supposedly replied, quote, Although the generator Faraday made was useful for demonstrations, it wouldn't produce very much useful current. That's because when you spun the disc, it would create current in the disc called eddy current that would get in the way of producing large current in the wires. In fact, it would take another 30 years before a cast of characters managed to make a useful generator. And that story is next time on the secret history of electricity. Thanks for watching my video. Please remember to give it a nice thumbs up. Have a good day.