The ancient Greeks knew for a long time that air would expand when heated. About 2000 years ago, Alexander's hero was actually a Greek living in Alexandria, Egypt. His name was Hero. He invented something similar to a steam engine, using the principle of thermal expansion, but it was not a thermometer. Until 1592, Galileo invented something like a thermometer, which can also measure air pressure. 16 12 years, Galileo's friend santorio santorio (1561-1636) modified Galileo's thermometer.

Until 17 13, Daniel Fahrenheit (1686- 1736) put a scale on the thermometer. First, he marked the melting temperature of ice and the temperature of healthy people, but he soon realized that the melting temperature of ice is constant, but the freezing temperature of water is changing. 1835, it was found that the normal temperature of human body was 98.6 degrees (that is, 37 degrees Celsius). Fahrenheit sometimes used alcohol as a liquid to indicate temperature, but later he chose mercury. Later, the upper limit of this thermometer was set to the boiling point of water, 2 12 degrees. This is the Fahrenheit temperature used in Britain and America.

1742, Swedish astronomer anders celsius (170 1- 1744) located the freezing point of water at 100, the boiling point of water at 0, and then Carolus Linnaeus (1707).

It is very unaccustomed to go from a country with one degree Celsius to a country with one degree Fahrenheit. It takes many years to get used to the Fahrenheit temperature. The specific conversion is F=(CX9/5)-32 and C=(F-32)X5/9, so it is still difficult to do mental arithmetic.

Kelvin introduced the concept of absolute zero in 1848, that is, minus 273.5 degrees Celsius, so zero degrees Celsius is 273. 15k, and 100 degrees Celsius is 373. 15K.

The hottest temperature recorded in the world is in Libya, the time is 1922, 13 September, and the temperature is 58 degrees Celsius. Then Mexico 60 degrees from 1953. The highest temperature recorded in the United States is in Death Valley, California,1965438+July, 2003 10, and the temperature is 56.7 degrees. Someone once described the feeling at this temperature. People can feel the threat of death, and the birds fall from the sky and are hot.