Ellen Gleditsch (Mandal, 1879 – Oslo, 1968) norwegian radiochemist and Norway's second female teacher. She began her career as an assistant to Marie Curie, pioneering radiochemistry and establishing the half-life of radium as well as helping to prove the existence of isotopes. She ran a radiochemistry laboratory in Norway, which was used as an underground laboratory to hide scientists fleeing the Nazi regime. She worked at UNESCO to combat illiteracy and in 1952 she resigned her post when Franco's Spain was admitted to UNESCO.