Alex Walker Jr., age 16, of Erie, Pa., for his question:

WHO WAS THE FIRST TO IDENTIFY NUCLEAR FISSION?

An Austrian Swedish physicist named Lise Meitner was the first to identify nuclear fission. She was born in Vienna in 1878 and educated at the universities of Vienna and Berlin.

In association with the German physicist Otto Hahn, Meitner helped discover the element protactinium in 1917. She was a professor of physics at the University of Berlin from 1926 until 1933.

In 1938, Meitner left Germany and became a member of the atomic research staff at the University of Stockholm. In 1939 she published the first paper concerning nuclear fission.

Meitner is also known for her research on atomic theory and radioactivity. In her work she predicted the existence of chain reactions, which contributed to the development of the atomic bomb.

In 1946 Meitner was visiting professor at the Catholic University in Washington, D.C. In 1959 she revisited the United States to lecture at Bryn Mawr College.