Curie_Marie5

__Explanation of Contributions__  Marie developed a new technique for investigating samples of uranium. Her husband had invented the electrometer, a device that measures low electrical currents. Marie used the electrometer to discover that uranium rays caused electricity in the air. The electricity was higher when there was more uranium present. The radioactivity of uranium depended on how much uranium there was. This proved that radiation is not caused by interaction of molecules, but comes from the atom itself. Back