Major Accomplishments
Marie Curie had many contributions to science. She discovered the radioactive elements polonium, radium, and thorium in December 1898. She found that these elements, along with uranium, were breaking up over time and releasing radiation which exposed the plate; this is radioactivity. This helped scientists analyze atoms' structures and showed that atoms could change in any way. This led to the discovery that atoms are made up of smaller particles. She also discovered that the amount of radiation did not depend on the size of the compound, but rather the amount of thorium or uranium it contained.