Ernest Rutherford

Today is the birthday of Ernest Rutherford, who was born in 1871 in Brightwater, New Zealand. Rutherford studied at Canterbury College in New Zealand and then at the University of Cambridge, where he developed an interest in radioactivity. In 1898 he left Britain to take up a professorship at McGill University in Canada. There, he and his collaborators discovered radioactive half-life, proved that radioactivity entailed the transmutation of one chemical element to another, and identified alpha and beta radiation. In 1907 Rutherford returned to Britain. At the University of Manchester he and his collaborators proved that alpha particles are helium nuclei. In perhaps his most famous experiment of all, Rutherford discovered that atoms consist of a tiny nucleus amid a considerably larger cloud of much lighter electrons. That discovery was made by firing alpha particles at a piece of thin gold foil and finding that 1 in 1800 of the nuclei recoiled. Rutherford described the experiment: “It was quite the most incredible event that has ever happened to me in my life. It was almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you.”

Date in History: 30 August 1871