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1200 BCE
Iron
About this time, the production of iron became widespread as that metal supplanted bronze. Iron was much more abundant than copper and tin, the two metals that make up bronze, and thus put metal tools into more hands than ever before. -
850 BCE
Gunpowder
Alchemists in China invented gunpowder as a result of their search for life-extending elixirs. It was used to propel rockets attached to arrows. The knowledge of gunpowder spread to Europe in the 13th century. -
Photography
n the early 1820s, Nicéphore Niépce became interested in using a light-sensitive solution to make copies of lithographs onto glass, zinc, and finally a pewter plate. He then had the great idea to use his solution to make a copy of an image in a camera obscura (a room or box with a small hole in one end through which an image of the outside is projected). In 1826 or 1827, he made an eight-hour-long exposure of the courtyard of his house, the first known photograph. -
Telegraph
Samuel Morse was a successful painter who became interested in the possibility of an electric telegraph in the 1830s. He patented a prototype in 1837. In 1844 he sent the first message over the first long-distance telegraph line, which stretched between Washington, D.C., and Baltimore. The message: “What hath God wrought.” -
1876: Telephone
Once it was possible to send information through a wire in the form of dots and dashes, the next step was actual voice communication. Alexander Graham Bell made the first telephone call, on March 10, 1876, when he asked his assistant Tom Watson to come to him: “Mr Watson—come here—I want to see you.” -
1879: Electric light
After thousands of trials, American inventor Thomas Edison got a carbon-filament light bulb to burn for 13½ hours. Edison and others in his laboratory were also working on an electrical power distribution system to light homes and businesses, and in 1882 the Edison Electric Illuminating Company opened the first power plant. -
1927: Television
Early television used a mechanical disk to scan an image. As a teenager in Utah, Philo T. Farnsworth became convinced that a mechanical system would not be able to scan and assemble images multiple times a second. Only an electronic system would do that. In 1922 the 16-year-old Farnsworth worked out a plan for such a system, but it wasn’t until 1927 that he made the first electronic television transmission, a horizontal line. -
1974: Personal computer
The first computers that emerged after World War II were gigantic, but, with advances in technology, especially in putting many transistors on a semiconductor chip, computers became both smaller and more powerful. Finally, they became small enough for home use. The first such personal computer was the Altair, which was soon supplanted in 1977 by the Apple II, the TRS-80, and the Commodore PET. -
1974: Internet
Vinton Cerf and Robert Kahn produced the TCP/IP (Transmission Control Protocol/Internet Protocol), which describes how data can be broken down into smaller pieces called packets and how these packets can be transmitted to the right destination. TCP/IP became the basis for how data is transmitted over the Internet. -
Artificial intelligence
The team behind the AlphaGo artificial intelligence program announced that it had become the world’s best go player. Go is a game with very simple rules but many possible positions. The previous year AlphaGo had defeated the great player Lee Sedol in a match 4–1. AlphaGo then played itself and, through continual improvement, was able to defeat the version that had defeated Lee, 100–0. Through machine learning, AlphaGo had become better at the game than any human.