|MadSci Network: Science History|
I suppose the most direct answer to your question, “Who was the first scientist to discover the Atom Bomb”? Would be Albert Einstein. He proposed the famous equation E=mc2 and wrote the letter to President Roosevelt suggesting the power of the atom could be used to make a weapon.
Really though many people played a role in the development of the Atomic Bomb.
Otto Hahn and Fritz Strassman working at the Kaiser Wilhelm institute in Berlin, and Lise Meitner working with Neilse Bohr in Copenhagen Denmark, found Barium in the residue from experiments in which they had bombarded uranium with neutrons. It appeared that the uranium when bombarded with neutrons had split into two different elements, each approximately half the mass of uranium.
Enrico Fermi, Herbert L Anderson and H.B. Hanstein showed that a chain reaction might be possible since the uranium emitted additional neutrons when it fissioned.
The atomic chain reaction was the result of the hard work of many hands and as many heads. Arthur H Compton, Walter Zin, Herbert Anderson, Loe Szilard, Eugene Wigner and 38 others created the first nuclear chain reaction on a Squash court under Stag Field at the University of Chicago at 3:20 pm December 2 1942. The chain reaction ran quietly until 3:53 pm 33 minutes.
Dr. J Robert Opinheimer and many other scientists joined this group of scientists, engineers and technicians, who worked at Los Alamos, where they designed, built and tested the first Atomic Bomb.
Supporting there work where thousands of engineers, and scientists as well as all types of trades people who built and operated Oak Ridge and Hanford where plutonium was produced and processed.
So in reality many people were responsible for the First Atomic Bomb.
The important point is that scientific breakthroughs are built on the works and discoveries of other scientists.
The following are some web sites you may want to visit.
I hope I have answered your question.
Try the links in the MadSci Library for more information on Science History.