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Spheroid (lithic)
In archaeology, a spheroid is a piece of rock that has been shaped into a nearly spherical shape ('' spheroidal''). Spheroids have been found at sites from as long ago as 1.8 million years. It is not known what their purpose was, but it has been speculated that they were used as projectiles in hunting. At one site ( Ubeidiya prehistoric site near the Sea of Galilee, 1.4 million years old) around 600 baseball-sized spheroids of limestone, basalt, and flint Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone. Historically, flint was widely used to make stone tools and start ... have been found, and it has been demonstrated that they were not simply hand axes that became spherical through use, but were deliberately made as spheres. References Lithics {{archaeology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeology
Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. The archaeological record consists of Artifact (archaeology), artifacts, architecture, biofact (archaeology), biofacts or ecofacts, archaeological site, 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. The discipline involves Survey (archaeology), surveying, Archaeological excavation, excavation, and eventually Post excavation, analysis of data collected, to learn more about the past. In broad scope, archaeology relies on cross-disciplinary research. 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. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spheroidal
A spheroid, also known as an ellipsoid of revolution or rotational ellipsoid, is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters. A spheroid has circular symmetry. If the ellipse is rotated about its major axis, the result is a ''prolate spheroid'', elongated like a rugby ball. The American football is similar but has a pointier end than a spheroid could. If the ellipse is rotated about its minor axis, the result is an ''oblate spheroid'', flattened like a lentil or a plain M&M. If the generating ellipse is a circle, the result is a sphere. Due to the combined effects of gravity and rotation, the figure of the Earth (and of all planets) is not quite a sphere, but instead is slightly flattened in the direction of its axis of rotation. For that reason, in cartography and geodesy the Earth is often approximated by an oblate spheroid, known as the reference ellipsoid, instead of a spher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ubeidiya Prehistoric Site
Ubeidiya (; ), some 3 km south of the Sea of Galilee, in the Jordan Rift Valley, Israel, is an archaeological site of the early Pleistocene, years ago, preserving traces of one of the early expansions of hominins out of Africa, earliest migrations of ''Homo erectus'' out of Africa, with (as of 2014) only the site of Dmanisi in Georgia (country), Georgia being older. The site yielded hand axes of the Acheulean type, but very few human remains. The animal remains include a hippopotamus' femur bone, and an immensely large pair of horns belonging to a species of extinct bovid. The site was discovered in 1959 and was first excavated between 1960 and 1974. The site is distinct from nearby Tell Ubeidiya. Etymology The prehistoric site is named for Ubeidiya, Tiberias, which was centered on Tell 'Ubeidiya but List of towns and villages depopulated during the 1947–1949 Palestine war, depopulated during the 1947–1949 Palestine war. The name Ubeidiya may be derived from the b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Of Galilee
The Sea of Galilee (, Judeo-Aramaic languages, Judeo-Aramaic: יַמּא דטבריא, גִּנֵּיסַר, ), also called Lake Tiberias, Genezareth Lake or Kinneret, is a freshwater lake in Israel. It is the lowest freshwater lake on Earth and the second-lowest lake in the world (after the Dead Sea, a salt lake), with its elevation fluctuating between below sea level (depending on rainfall). It is approximately in circumference, about long, and wide. Its area is at its fullest, and its maximum depth is approximately .Data Summary: Lake Kinneret (Sea of Galilee) The lake is fed partly by underground springs, but its main source is the Jordan River, which flows through it from north to south with the outflow controlled by the Degania Dam. |
Baseball (ball)
A baseball is the ball used in the sport of baseball. It consists of a rubber or cork center wrapped in yarn and covered with white natural horsehide or cowhide, or a synthetic composite leather. A regulation baseball is in circumference i.e. in diameter, with a weight of . The leather cover is commonly formed from two saddle-shaped pieces stitched together, typically with red-dyed thread. There are 108 stitches on a regulation baseball. That stitching plays a significant role in the trajectory of a thrown baseball due to the drag caused by the interaction between the stitching and the air. Controlling the orientation of the stitches and the speed of the ball's rotation allows a pitcher to affect the behavior of the pitched ball in specific ways. Commonly employed pitches include the curveball, the slider, the two-seam fastball, the four-seam fastball, the sinker, the cutter and the changeup. History In the early, mid-1800s days of baseball, there was a great variety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science), crystal forms of calcium carbonate . Limestone forms when these minerals Precipitation (chemistry), precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly Dolomite (rock), dolomite, a closely related rock, which contains a high percentage of the mineral Dolomite (mine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basalt
Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial planet, rocky planet or natural satellite, moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt is chemically equivalent to slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of volcanism on Venus, Venus, which cover ~80% of the surface, are basaltic; the lunar mare, lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars. Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flint
Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone. Historically, flint was widely used to make stone tools and start fires. Flint occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones.''The Flints from Portsdown Hill'' Inside the nodule, flint is usually dark grey or black, green, white, or brown in colour, and has a glassy or waxy appearance. A thin, oxidised layer on the outside of the nodules is usually different in colour, typically white and rough in texture. The nodules can often be found along s and [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hand Ax
A hand axe (or handaxe or Acheulean hand axe) is a prehistoric stone tool with two faces that is the longest-used tool in human history. It is made from stone, usually flint or chert that has been "reduced" and shaped from a larger piece by knapping, or hitting against another stone. They are characteristic of the lower Acheulean and middle Palaeolithic (Mousterian) periods, roughly 1.6 million years ago to about 100,000 years ago, and used by ''Homo erectus'' and other early humans, but rarely by ''Homo sapiens''. Their technical name (biface) comes from the fact that the archetypical model is a generally bifacial (with two wide sides or faces) and almond-shaped (amygdaloidal) lithic flake. Hand axes tend to be symmetrical along their longitudinal axis and formed by pressure or percussion. The most common hand axes have a pointed end and rounded base, which gives them their characteristic almond shape, and both faces have been knapped to remove the natural cortex, at least part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
