An electromagnet is a type of magnet in which the magnetic field is produced by an electric current, and disappears when the current is turned off.
Electromagnets usually consist of a large number of closely spaced turns of wire that create the magnetic field.
On February 11, 1864, Dr. Emmett Brown and his son Jules built an electromagnet from the electric magnetic machine that was unsuccessfully marketed to General Ulysses S. Clayton during an American Civil War campaign known as the Battle of Chattanooga. When they powered it up, it attracted all the weapons from both the Confederate and Union soldiers.
In September 1984, Doc made an electromagnet from a wire wrapped around a metal rod and the car battery that powered his electric hoe. He loaned them to Marty for the science project that his teacher, Mrs. Zawadski, had assigned.
In 1991, Doc accessed the video encyclopedia to display an experiment titled E for Electromagnet, where his lab assistant Bill Nye created an electromagnet by using two batteries with a length of wire wrapped around a screwdriver.
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