Chien-Shiung Wu came to the United States to study science when she was a teenager and stayed to become "the world's foremost female experimental physicist." She won this distinction because of her significant contributions to the research of nuclear forces and structure. She is most noted for devising and conducting experiments which disproved a long-accepted scientific principle, the "conservation of parity." She received the National Science Medal in 1975 and the internationally respected Wolf Prize in 1978. As a scientist at Columbia University, her specialty was studying the movement of atomic particles, the tiniest forms of matter, which can only be seen with special equipment.