During the Great Depression, the federal government began funding scientific research on a grand scale. Spurred on by the necessities of war, that precedent accelerated during WWII, and continued afterward. Some of this century's most significant scientific and technological accomplishments took place in the 1940s.

• An injectable form of penicillin was developed by 1941 as an effective antibiotic against many of the common bacteria that infect humans.
• Sulfanilamide was used successfully to treat bacterial infections in 1941.
• Dried blood plasma, first used on the battlefield, helped 96 percent of wounded United States servicemen survive.
• Streptomycin, one of several new miracle drugs used to treat tuberculosis, pneumonia, meningitis, and typhoid fever was developed in 1943.
• DDT was introduced in the United States to kill disease-carrying and crop-destroying insects.
• Radar, invented by the British as a means to track airplanes, revolutionized commercial aviation after the war.
• The genetic role of DNA was demonstrated in 1943.
• Synthetic quinine was developed to treat malaria in 1944.
• A cure for cholera was developed in 1945.
• In 1946 Lawrence Bell perfected the helicopter, first developed in 1939.
• The first products were sold commercially under the trademark Teflon ® beginning in 1946.
• Edwin Land introduced the Polaroid Land Camera and instant photography in 1947.
• The Reynolds Metal Company introduced aluminum foil for home use in 1947.
• Jet engine flight, first advanced during the war, developed in the late 1940s.
• Charles Yeager broke the sound barrier in 1947, ushering in the age of supersonic flight.
• Dr. Jonas Salk isolated the polio virus in 1948.
• Three American physicists working at Bell Laboratories in 1948 invented the transistor, which replaced the vacuum tube in radios, televisions, computers, and other electronic devices.
• Velcro was invented in 1948.