Simplify the following text for a Grade 11 native English-speaking person.
Original: Berkeley physicists worked on the Manhattan Project during World War II and the university now manages the nation 's two principal nuclear weapons laboratories : Lawrence Berkeley National Laboratory and Los Alamos National Laboratory .
Simplified: Berkeley physicist J. Robert Oppenheimer was the scientific director of the Manhattan Project that developed the first atomic bomb in the world , which he personally headquartered at Los Alamos , New Mexico , during World War II . Since that time , the university has co-managed the Los Alamos National Laboratory , as well as the Lawrence Livermore National Laboratory and Lawrence Berkeley National Laboratory for the U.S. Department of Energy .