Radar is short for RAdio Detection And Ranging. Radar is used to locate distant objects by sending out radio waves and analyzing the echos that return. Radar can determine where a distant object is, how big it is, what shape it has, how fast it's moving and in which direction it's going. Radar is now used to watch developing weather patterns, to monitor air traffic, to track ships at sea, and to detect missiles.

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The first electric refrigerator was invented in 1803 by Thomas Moore. The first commercial refrigerator designed to keep food cold was sold in 1911 (by the General Electric Company) and in 1913 (invented by Fred W. Wolf of Fort Wayne, Indiana, USA); these model consisted of a unit that was mounted on top of an ice box. A self-contained refrigerator (with a compressor on the bottom of the cabinet) was invented by Alfred Mellowes in 1915. Mellowes produced this refrigerator commercially (each unit was hand made), but was bought out by W.C. Durant (the president of General Motors) in 1918, who started the Frigidaire Company in order to mass-produce refrigerators in the USA.

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John H. Patterson (1844-1922) bought Ritty's patent and his cash register company in 1884. Patterson renamed the Dayton, Ohio, company the National Cash Register Company. Patterson improved Ritty's cash register by adding a paper tape that kept a printed record of all transactions.

In 1906, Charles F. Kettering (and employee of NCR) developed an electric cash register (Kettering later worked for General Motors and invented the electric car ignition).

The National Cash Register Company was later called NCR, until the company was bought by ATT in 1991; it was given back the name NCR in 1996, when it was split off from ATT.

After many years of failed attempts and public ridicule, Goddard's first successful rocket was launched on March 16, 1926 from a relative's farm in Auburn, Massachusetts. It was a liquid-fueled 10-ft. rocket that he called Nell. The flight lasted 2 1/2 seconds; the rocket flew a distance of 184 feet and achieved an altitude of 41 feet.

Goddard soon moved to Roswell, New Mexico, where he developed more sophisticated multi-stage rockets, rockets with fins (vanes) to steer them (1932), a gyro control device to control the rocket (1932), and supersonic rockets (1935). In 1937, Goddard launched the first rocket with a pivotable motor on gimbals using his gyro control device. Altogether, Robert Goddard had 214 patents.

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