The one that [Made in Poland] chose to sacrifice was particularly nasty and greasy, but after popping off the pulley, the treasure within was revealed: the large, ring-shaped clutch electromagnet.

Morse in 1832. Other inventors experimented with sending messages using electrical signals, but his was the first to successfully combine a simple code with a transmitting and receiving device.

A coil with an iron core is called an electromagnet. The iron core increases the coil’s magnetic field strength. A simple electromagnet is made by coiling wire around an iron nail. An iron core ...