Science advanced dramatically during the 20th century. There were new and radical developments in the physical, life and human sciences, building on the progress made in the 19th century. The development of post-Newtonian theories in physics, such as special relativity, general relativity, and quantum mechanics led to the development of nuclear weapons. New models of the structure of the atom led to developments in theories of chemistry and the development of new materials such as nylon and plastics. Advances in biology led to large increases in food production, as well as the elimination of diseases such as polio.