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Calibrated Years
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. The method was developed in the late 1940s at the University of Chicago by Willard Libby. It is based on the fact that radiocarbon () is constantly being created in the Earth's atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and thereafter the amount of it contains begins to decrease as the undergoes radioactive decay. Measuring the amount of in a sample from a dead plant or animal, such as a piece of wood or a fragment of bone, provides information that can be used to calc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronological Dating
Chronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing such object or event to be located in a previously established chronology. This usually requires what is commonly known as a "dating method". Several dating methods exist, depending on different criteria and techniques, and some very well known examples of disciplines using such techniques are, for example, history, archaeology, geology, paleontology, astronomy and even forensic science, since in the latter it is sometimes necessary to investigate the moment in the past during which the death of a cadaver occurred. These methods are typically identified as absolute, which involves a specified date or date range, or relative, which refers to dating which places artifacts or events on a timeline relative to other events and/or artifacts. Other markers can help place an artifact or event in a chronology, such as nearby writings and stratigraphic markers. Absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Fuels
A fossil fuel is a hydrocarbon-containing material formed naturally in the Earth's crust from the remains of dead plants and animals that is extracted and burned as a fuel. The main fossil fuels are coal, oil, and natural gas. Fossil fuels may be burned to provide heat for use directly (such as for cooking or heating), to power engines (such as internal combustion engines in motor vehicles), or to generate electricity. Some fossil fuels are refined into derivatives such as kerosene, gasoline and propane before burning. The origin of fossil fuels is the anaerobic decomposition of buried dead organisms, containing organic molecules created by photosynthesis. The conversion from these materials to high-carbon fossil fuels typically require a geological process of millions of years. In 2019, 84% of primary energy consumption in the world and 64% of its electricity was from fossil fuels. The large-scale burning of fossil fuels causes serious environmental damage. Over 80% of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philadelphia
Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania, the sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. Since 1854, the city has been coextensive with Philadelphia County, the most populous county in Pennsylvania and the urban core of the Delaware Valley, the nation's seventh-largest and one of world's largest metropolitan regions, with 6.245 million residents . The city's population at the 2020 census was 1,603,797, and over 56 million people live within of Philadelphia. Philadelphia was founded in 1682 by William Penn, an English Quaker. The city served as capital of the Pennsylvania Colony during the British colonial era and went on to play a historic and vital role as the central meeting place for the nation's founding fathers whose plans and actions in Philadelphia ultimately inspired the American Revolution and the nation's inde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franklin Institute
The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and statesman Benjamin Franklin. It houses the Benjamin Franklin National Memorial. Founded in 1824, the Franklin Institute is one of the oldest centers of science education and development in the United States. Its chief astronomer is Derrick Pitts. History On February 5, 1824, Samuel Vaughan Merrick and William H. Keating founded the Franklin Institute of the State of Pennsylvania for the Promotion of the Mechanic Arts. Begun in 1825, the institute was an important force in the professionalization of American science and technology through the nineteenth century, beginning with early investigations into steam engines and water power. In addition to conducting scientific inquiry, it fostered research and education by running schools, publishing the influential ''Journal of The Franklin Institute'', sponsoring e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serge A
Serge may refer to: *Serge (fabric), a type of twill fabric *Serge (llama) (born 2005), a llama in the Cirque Franco-Italien and internet meme *Serge (name), a masculine given name (includes a list of people with this name) *Serge (post), a hitching post used among the Buryats and Yakuts *Serge synthesizer, a modular synthesizer See also *Overlock, a type of stitch known as "serger" in North America *Surge (other) *Serg (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lawrence Radiation Laboratory
Lawrence may refer to: Education Colleges and universities * Lawrence Technological University, a university in Southfield, Michigan, United States * Lawrence University, a liberal arts university in Appleton, Wisconsin, United States Preparatory & high schools * Lawrence Academy at Groton, a preparatory school in Groton, Massachusetts, United States * Lawrence College, Ghora Gali, a high school in Pakistan * Lawrence School, Lovedale, a high school in India * The Lawrence School, Sanawar, a high school in India Research laboratories * Lawrence Berkeley National Laboratory, United States * Lawrence Livermore National Laboratory, United States People * Lawrence (given name), including a list of people with the name * Lawrence (surname), including a list of people with the name * Lawrence (band), an American soul-pop group * Lawrence (judge royal) (died after 1180), Hungarian nobleman, Judge royal 1164–1172 * Lawrence (musician), Lawrence Hayward (born 1961), British musician * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sam Ruben
Samuel Ruben (born Charles Rubenstein; November 5, 1913 – September 28, 1943) was an American chemist who with Martin Kamen co-discovered the synthesis of the isotope carbon-14 in 1940. Early life Ruben was the son of Herschel and Frieda Penn Rubenstein – the name was officially shortened to Ruben in 1930. Young Sam developed a friendship with neighbor Jack Dempsey and became involved with a local boys' boxing club and later, when the family moved across the Bay to Berkeley, he was a successful basketball player at Berkeley High School (Berkeley, California). After achieving his B.S. in Chemistry at the University of California, Berkeley, he continued his studies there and was awarded a Ph.D. in physical chemistry in May 1938. He was immediately appointed instructor in the Chemistry Department, and became an assistant professor in 1941. Research Ruben and colleague Martin Kamen, a University of Chicago Ph.D. and researcher in chemistry and nuclear physics working under Er ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Martin Kamen
Martin David Kamen (August 27, 1913, Toronto – August 31, 2002, Montecito, California) was an American chemist who, together with Sam Ruben, co-discovered the synthesis of the isotope carbon-14 on February 27, 1940, at the University of California Radiation Laboratory, Berkeley. He also confirmed that all of the oxygen released in photosynthesis comes from water, not carbon dioxide, in 1941. Kamen was the first to use carbon-14 to study a biochemical system, and his work revolutionized biochemistry and molecular biology, enabling scientists to trace a wide variety of biological reactions and processes. Despite being blacklisted for nearly a decade on suspicion of being a security risk, Kamen went on to receive the Albert Einstein World Award of Science in 1989, and the U.S. Department of Energy's 1995 Enrico Fermi award for lifetime scientific achievement. Early life and education Kamen was born on August 27, 1913, in Toronto, the son of Russian Jewish immigrants. He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronze Age
The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second principal period of the three-age system proposed in 1836 by Christian Jürgensen Thomsen for classifying and studying ancient societies and history. An ancient civilization is deemed to be part of the Bronze Age because it either produced bronze by smelting its own copper and alloying it with tin, arsenic, or other metals, or traded other items for bronze from production areas elsewhere. Bronze is harder and more durable than the other metals available at the time, allowing Bronze Age civilizations to gain a technological advantage. While terrestrial iron is naturally abundant, the higher temperature required for smelting, , in addition to the greater difficulty of working with the metal, placed it out of reach of common use until the end o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neolithic
The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts of the world. This "Neolithic package" included the introduction of farming, domestication of animals, and change from a hunter-gatherer lifestyle to one of settlement. It began about 12,000 years ago when farming appeared in the Epipalaeolithic Near East, and later in other parts of the world. The Neolithic lasted in the Near East until the transitional period of the Chalcolithic (Copper Age) from about 6,500 years ago (4500 BC), marked by the development of metallurgy, leading up to the Bronze Age and Iron Age. In other places the Neolithic followed the Mesolithic (Middle Stone Age) and then lasted until later. In Ancient Egypt, the Neolithic lasted until the Protodynastic period, 3150 BC.Karin Sowada and Peter Grave. Egypt in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Younger Dryas
The Younger Dryas (c. 12,900 to 11,700 years BP) was a return to glacial conditions which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM, c. 27,000 to 20,000 years BP). The Younger Dryas was the last stage of the Pleistocene epoch (c. 2,580,000 to 11,700 years BP) and it preceded the current, warmer Holocene epoch. The Younger Dryas was the most severe and long lasting of several interruptions to the warming of the Earth's climate, and it was preceded by the Late Glacial Interstadial (c. 14,670 to 12,900 BP). The change was relatively sudden, taking place in decades, and it resulted in a decline of temperatures in Greenland by 4~10 °C (7.2~18 °F), and advances of glaciers and drier conditions over much of the temperate Northern Hemisphere. A number of theories have been put forward about the cause, and the most widely supported by scientists is that the Atlantic meridional overturning circulation, which transports warm water fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeology
Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscapes. Archaeology can be considered both a social science and a branch of the humanities. It is usually considered an independent academic discipline, but may also be classified as part of anthropology (in North America – the four-field approach), history or geography. Archaeologists study human prehistory and history, from the development of the first stone tools at Lomekwi in East Africa 3.3 million years ago up until recent decades. Archaeology is distinct from palaeontology, which is the study of fossil remains. Archaeology is particularly important for learning about prehistoric societies, for which, by definition, there are no written records. Prehistory includes over 99% of the human past, from the Paleolithic until the adven ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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