December 2

Enrico Fermi's research group produces a controlled nuclear reaction.

On this day in 1942, Enrico Fermi split an atom into parts for the first time ever. Fermi knew that if he could make a neutron break away from an atom's nucleus, he would have a new source of energy. The work was very dangerous, and he was afraid he might blow up most of Chicago! Luckily, the experiment, called controlled nuclear fission, was a success.