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Rain gauge. A rain gauge (also known as udometer, pluviometer, ombrometer, and hyetometer) is an instrument used by meteorologists and hydrologists to gather and measure the amount of liquid precipitation over a predefined area, over a period of time. [1] It is used to determine the depth of precipitation (usually in mm) that occurs over a unit ...
Taiwan,[II][k] officially the Republic of China (ROC),[I][l] is a country[27] in East Asia.[o] It is located at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the northeast, and the Philippines to the south. The territories controlled by the ...
ISO 8601 is an international standard covering the worldwide exchange and communication of date and time-related data. It is maintained by the International Organization for Standardization (ISO) and was first published in 1988, with updates in 1991, 2000, 2004, and 2019, and an amendment in 2022.[1] The standard provides a well-defined ...
Daylight saving time. Daylight saving time ( DST ), also referred to as daylight saving (s), daylight savings time, daylight time (United States and Canada), or summer time ( United Kingdom, European Union, and others), is the practice of advancing clocks to make better use of the longer daylight available during summer, so that darkness falls ...
The Sun is the star at the center of the Solar System. It is a massive, nearly perfect ball of hot plasma,[18][19] heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light and infrared radiation with 10% at ultraviolet energies. It is by far the most important source of ...
The number π (/paɪ/; spelled out as "pi") is a mathematical constant that is the ratio of a circle's circumference to its diameter, approximately equal to 3.14159. The number π appears in many formulae across mathematics and physics. It is an irrational number, meaning that it cannot be expressed exactly as a ratio of two integers, although ...
1989 Tiananmen Square protests and massacre. / 39.90333°N 116.39167°E / 39.90333; 116.39167. The Tiananmen Square protests, known in China as the June Fourth Incident, [1] [2] [a] were student-led demonstrations held in Tiananmen Square, Beijing, China, lasting from 15 April to 4 June 1989. After weeks of unsuccessful attempts between ...
