Scientific Discoveries By Whitney.Chandler Period: Apr 21, 1905 to Apr 21, 2014 Discoveries Apr 21, 1906 Third Law of Thermodynamics Apr 21, 1911 Automic Nucleus Apr 21, 1913 Bohr Atom Model Apr 21, 1932 Neutron Apr 21, 1938 Nucleur Fission Apr 21, 1943 DNA on Chromosome Apr 21, 1953 Helical structure of DNA Apr 21, 1997 First Clone Apr 21, 2001 First draft of human genone