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December 20 Science History

Science History of December 20

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Learn about the history of science by reading about the significant scientific events that took place on this day in history.

2002 - Grote Reber died.

Grote Reber (1911 - 2002)
National Radio Astronomy Observatory/National Science Foundation
Reber was an American amateur radio operator and astronomer who built the first radio telescope. After learning about Karl Jansky's discovery of radio signals from space, he built a 9-meter dish receiver in his back yard. He began a systematic mapping of radio frequencies of the night sky. His success began the radio observatory boom of modern astronomy.

1998 - Alan Lloyd Hodgkin died.

Hodgkin was a British biophysicist who shares the 1963 Nobel Prize in Medicine with John Eccles and Andrew Huxley for their research into nerve cells. They discovered the chemical processes that dictate the passage of impulses along nerve fibers.

1996 - Carl Sagan died.

Carl Sagan (1934 - 1996)
NASA/JPL
Sagan was an American astronomer who popularized astronomy and astrophysics through a successful 13 part television program called "Cosmos: A Personal Voyage". He also supported efforts to search for evidence of extra-terrestrial life and the SETI (Search for Extra-Terrestrial Intelligence) program. He was among the first to recognize Saturn's moon, Titan could support oceans that could support life and the surface of Venus was more likely to be extremely hot and dry rather than stormy.

1921 - Richard Julius Petri died.

A Petri dish is a shallow cylindrical dish that has a lid.
Szalka Petriego
Petri was a German biologist who is credited with the invention of the petri dish while working as an assistant to Robert Koch. This shallow glass cylinder is used to culture cells and bacteria.

1915 - Thomas Leopold Willson died.

Willson was a Canadian chemist and inventor who discovered an economical method to create calcium carbide and its by-product acetylene. He dumped his waste slag from an electric furnace producing aluminum into a nearby stream and obsserved a burst of flame. Further investigation showed that adding water to the slag would produce calcium carbide and acetylene. He also was the inventor of over sixty inventions including electric arc lighting and gas navigational buoys.

1901 - Robert Jemison Van de Graaff was born.

Robert J. Van de Graaff (1901 - 1967)
Wikimedia Commons
Van de Graaff was the American physicist who designed the Van de Graaff generator. The Van de Graaff is a generator capable of generating high voltages of static electricity. It uses an insulated motorized belt to transfer charge from a power source to the surface of a conducting sphere. They are capable of generating voltages of up to approximately 20 million volts and are usually used to demonstrate the effects of high DC voltage.

1890 - Jaroslav Heyrovsky was born.

Heyrovsky was a Czech chemist who was awarded the 1959 Nobel Prize in Chemistry for the development of polarography. Polarography is an analytical tool that uses a dropping mercury electrode (DME) to investigate the effects of varying currents and potentials of a compound. It was the first successful voltametry technique and the beginning of a new method of analytical chemistry. Voltametry is a useful technique to use as a sensor to monitor chemical levels remotely in industrial, biological or hazardous situations.

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