- William Sturgeon was an English electrical engineer who built the first working electromagnet in 1825. When Sturgeon was at the Royal Academy of Woolwich, he and Francis Watkins made the first practical electromagnet using a horseshoe shaped piece of iron and adding 16 loops of wire to it. After running electricity through it, it could pick up 9 pounds of metal. Sturgeon received the silver medal of Royal Society of Arts in 1825 when he put it on exhibition in London that year.
- An electromagnet works by using a conductive, coiled wire and electricity. First, the wire must be insulated to keep it from touching the iron core. If it isn't insulated, it can cause an electrical short and the current would pass through the core. Second, the wire is wrapped repeatedly around the core and when electricity flows through it, the core becomes magnetized. The magnetic field is generated by the looping of wires; the more wires, the more strength it will have. Electromagnets don't need an iron core, and if they don't have one, they are referred to as solenoids.
- Electromagnets have practical uses, like the one William Sturgeon demonstrated. Today, the idea of using metal to lift other metal is what allows junkyard cranes to pick up cars. After turning on the electromagnet, the magnetism allows the car to be lifted. When dumping the car, the magnet is just shut off. Electromagnets also help create sound in speakers. The coil becomes magnetized, it moves. This movement also moves the paper cone of the speaker. By changing the direction of the current, the paper cone can be pushed or pulled. This pattern creates sound waves.
- A solenoid is an electromagnet that produces a field similar to a bar magnet. The magnetic lines loop through the center of the wire column and then out again. However, most electromagnets are considered iron core solenoids. This means that the wires loop around an iron core. This makes the internal magnetic domains of the iron line up with the driving magnetic field produced by the solenoid. The result is a field strength multiplied by the iron core that can be tens to thousands of times greater.
- The direction of electricity and the direction of current are related to each other. When electricity is flowing away from you, the magnetic field circulates clockwise. If the direction of electricity is flowing towards you, the magnetic field flows counter-clockwise. Also, magnetic fields don't have a permanent north or south pole, which means they switch depending on which direction the electricity moves.
