Radio
History of Radio from 1895-1945, How Stuff Works: How Radio Works, Radio Design Group: How Radios Work
Telephones
Antique Telephone History, HowStuffWorks: Telephones, Invention of the Telephone, Routing Calls Through the Network, Smithsonian: Box Telephone, The History of the Telephone
Televisions
How Television Works, Howstuffworks.com: How Television Works, Invention of Television, Radio Design Group: How Television Works, The American Experience: Big Dream Small Screen
Aadi's School Science Project
Contains details of scientific inventions, scientists, space & astronomy.
Inventions at Nationalgeographic.com
Encounter some of the world's most interesting inventions while helping Professor Lou Knee fire up his latest gadget.
Reinvent the Past: Famous Inventions
Find out how the airplane, automobile, light bulb, telegraph, and bifocal glasses came into existence in this Thinkquest Junior site.
Smith College Museum of Ancient Inventions
Virtual museum includes photographs and brief descriptions of the tools of a bygone era.
Totally Absurd Inventions
From the tricycle lawn mower to the diaper alarm, read about some of the strangest patents ever applied for.