Answer:
Steel
The Chinese of the Warring States Period (403–221 BC) had quench-hardened steel, while the Chinese of the Han Dynasty (202 BC – 220 AD) produced steel by combining wrought iron with cast iron together, obtaining an ultimate carbon-intermediate steel commodity by the 1st century A.D.
Refrigerator
William Cullen at the University of Glasgow demonstrated the first artificial refrigeration system in the year 1748. However, he never used his discovery for practical purposes. In the year 1805, US inventor Oliver Evans, designed the first refrigeration machine that didn't use liquid and instead used vapor to cool.
Mechanical Computer
Charles Babbage started building a small differential engine in c. 1819, and finished by 1822 (Difference Engine 0). On 14 June 1822, in a paper to the Royal Astronomical Society, he announced his discovery, entitled "Note on the application of machinery to computing astronomical and mathematical tables.
Airplane
Wilbur and Orville Wright made four brief flights with their first electric aircraft at Kitty Hawk on 17 December 1903. The first effective plane had been designed by the Wright brothers. To time the Kitty Hawk flights the Wrights used the stopwatch.
Electric Television
On 7 Sept. 1927, electronic television was seen successfully in San Francisco for the first time. The machine was developed by the 21-year-old inventor Philo Taylor Farnsworth who had lived in a house without electricity until he was 14.
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