Thomson announces the discovery of electrons. On April 30, 1897, British physicist J.J. Thomson announced his discovery that atoms were made up of smaller components. This finding revolutionized the way scientists thought about the atom and had major ramifications for the field of physics.

Who is JJ Thomson and what did he discover?

In 1897, J.J. Thomson discovered the electron by experimenting with a Crookes, or cathode ray, tube. He demonstrated that cathode rays were negatively charged. In addition, he also studied positively charged particles in neon gas.

What are 3 discoveries from Thomson's experiment?

In Thomson's first experiment, he discovered that cathode rays and the charge they deposited were intrinsically linked together. In the second experiment, he discovered that the charge in the cathode rays was negative. He deduced that the cathode rays were made up of negatively-charged particles.