|
Year |
Event(s) |
1 | 1920 | - The Band-Aid invented by Earle Dickson
- The tommy gun patented by John T Thompson.
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2 | 1921 | - Artificial life begins -- the first robot built.
- Calvin Coolidge president of the USA 1921-1929. Calvin Coolidge, vice president under Warren Harding, sworn in as president the day after Harding dies.
- John Larson, a University of California medical student, invented the modern lie detector (polygraph), used by police since 1924.
- Warren Harding president of the USA 1921. Warren Harding dies of an embolism in San Francisco. He had taken ill on 31 Jul 1921.
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3 | 1922 | - Insulin invented by Sir Frederick Grant Banting.
- The first 3-D movie (spectacles with one red and one green lens) is released.
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4 | 1923 | - Clarence Birdseye invents frozen food.
- Garrett A. Morgan invents a traffic signal.
- John Harwood invented the self-winding watch.
- The television or iconoscope (cathode-ray tube) invented by Vladimir Kosma Zworykin.
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5 | 1924 | - Notebooks with spiral bindings invented.
- The dynamic loudspeaker invented by Rice and Kellogg.
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6 | 1925 | - The mechanical television a precursor to the modern television, invented by John Logie Baird.
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