John Kerr (physicist)

John Kerr was a smart man who liked to use his brain to figure out how things work. He was especially interested in electricity and how it can make things move. He found out that when you put electricity into a certain kind of material called a crystal, the crystal bends and twists. This is called the Kerr effect. John Kerr discovered this effect in 1875 and people still use it today to help make things like cameras, televisions, and even lasers work better. So, John Kerr was a really important person in the world of physics!