One easy rule for estimating temperature in Fahrenheit is to double the temperature in Celsius and add 30°. Another simple method is to remember this poem by Carole Greenes, Boston University: 30° is hot, 20° is pleasing, 10° is not, 0° is freezing. A meter is a “big yard,” while a liter is a “big quart.” A ton is 2000 lb. A metric ton is 1000 kg.The difference is 200 lb or about 91 kg. At sunset, the temperature at the moon’s equator is about 58° F. During the night, it drops to about –261° F. The highest temperature ever recorded in the United States was 134° F on July 10, 1913, at Death Valley, California. German physicist Daniel Gabriel Fahrenheit (1686–1736) invented the mercury thermometer in 1714. Before then, thermometers contained alcohol. Swedish astronomer Anders Celsius (1701–1744) introduced his scale in 1742. The Celsius scale has become part of the metric system of measurement and is used throughout the world.
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