Science & Philosophy: Adam Smith Biography to Spectroscopic binary
Snails
Snails are mollusks typically with a coiled, more or less helical, shell as their most conspicuous external feature. When active, snails creep on a broad muscular foot, and display a head with eyes and sensory tentacles. Inside the shell is an asymmetrical visceral mass and one or more gills or lungs used for respiration. Beneath the head is a mouth equipped with a radula, a spiky, long, rasping t…
Snakeflies
Snakeflies are insects in the family Raphidiidae, in the order Neuroptera, which also contains the closely related alderflies (Sialidae) and dobsonflies (Corydalidae). There are not many species of snakeflies. The approximately 20 species that occur in North America are all western in their distributions. Snakeflies have a complete metamorphosis, with four stages in their life history: egg, larva,…
Snakes - Evolution, Snakes And Humans - Appearance and behavior
Snakes are limbless reptiles with an elongated, cylindrical body, scaly skin, lidless eyes, and a forked tongue. Most species are non-venomous, some are mildly venomous, and others produce a deadly venom. All snakes are carnivores (or meat-eaters). They are also cold blooded (or ectotherms), meaning their body temperature is determined by the environment, rather than being internally regulated (ho…
Snapdragon Family
The snapdragon or figwort family (Scrophulariaceae), class Dicotyledon, is composed of about 3-4,000 Indian paintbrush (Castilleja sp.). Photograph by Robert J. Huffman. Field Mark Publications. Reproduced by permission. species and 200 genera of vascular plants. Species in this family occur on all continents except Antarctica, but are most diverse in temperate and mountain ecosystems. Mo…
Sociability in African Thought - Bibliography
Sociability is a descriptive term that refers to the relational or interactive disposition and condition from which persons, as individuals, are said to derive their identity and status. According to this view, humans are regarded as beings whose defining characteristics, like reason, and its manifestation in cognitive, moral, and language capacities, are said to arise from the social conditioning…
Social Capital - Bibliography
The term social capital first began to be defined in the 1970s and remained largely restricted to the academic world of the social sciences until the 1990s, when it suddenly emerged as a central element in public discussions and policy debates about the quality of civic culture in Western nations, especially the United States of America. At the same time it also gained a place of prominence in dis…
Social Contract - Modern Formulations, Political Authority Versus Moral Principles, Hobbes And Rawls, Feminist Views, Bibliography
Modern theorists of the social contract school argued that political authority was artificial and conventional rather than divinely or naturally ordained. To sustain their argument, some—including Thomas Hobbes (1588–1679), John Locke (1632–1704), and Jean-Jacques Rousseau (1712–1778)—appealed to a social contract as a way of explaining the rational basis for and…
U.S. Social History - Bibliography
The "new" social history that emerged in the United States in the 1960s and came to dominate the profession by the 1980s, conjoined two scholarly agendas. The first was a program for reshaping history along the lines of the behavioral sciences—in particular economics, political science, and sociology—and employing quantitative methods and models in historical research. …
Socialism - Industrial Revolution And The Rise Of Socialism, Utopian Socialists: Owen, Saint-simon, Fourier
The difficulty of defining socialism is apparent to anyone who attempts to study this protean doctrine, not least because what socialism is or is not is usually a matter of contentious debate. However, there is a general consensus that the various schools of socialism share some common features that can be summarized as follows. Socialism is above all concerned with the relationship between the in…
African Socialisms - North African, "arab" Socialisms, African Socialists, Afro-marxism, Conclusion, Bibliography
Socialist ideas have been in Africa before the advent of colonialism at the turn of the nineteenth century. African socialisms represent various combinations of African thinkers, politicians, and activists' absorption with and reconfiguring of nineteenth-and twentieth-century European socialist ideas and practice. The sources are multiple, from trades unions and contact with European worker…
Sociobiology
Sociobiology, also called behavioral ecology, is the study of the evolution of social behavior in all organisms, including human beings. The highly complex behaviors of individual animals become even more intricate when interactions among groups of animals are considered. Animal behavior within groups is known as social behavior. Sociobiology asks about the evolutionary advantages contributed by s…
Sodium Hydroxide - Sodium hydroxide in household products, Industrial uses of sodium hydroxide
Sodium hydroxide, NaOH, also known as lye or caustic soda, is an extremely caustic (corrosive and damaging to human tissue) white solid that readily dissolves in water. Sodium hydroxide is used in the manufacture of soaps, rayon, and paper, in petroleum refining, and in homes as drain cleaners and oven cleaners. Sodium hydroxide is one of the strongest bases commonly used in industry. Solutions of…
Sodium Hypochlorite
Sodium hypochlorite (NaOCl) is a chemical compound consisting of sodium, oxygen, and chlorine that has been used for centuries for bleaching and disinfecting. Today, sodium hypochlorite (commonly called chorine bleach) is mass produced by the chlorination of soda ash and is employed in many household products, including laundry bleaches, hard surface cleaners, mold and mildew removers, and drain c…
Soil - Soil Formation, Soil Profiles And Horizons, Aging Soils, Soil Categories, Soil Groups And Agriculture
Soil is a complex mixture of pulverized rock and decaying organic matter, which covers most of the terrestrial surface of the Earth. Soil not only supports a huge number of organisms below its surface—bacteria, fungi, worms, insects and small mammals, which all play a role in soil formation—but it is essential to all life on Earth. Soil provides a medium in which plants can grow, sup…
Soil Conservation - History, How Soil Erodes, Soil Conservation Methods, Barrier Approaches, Cover Approaches
Soil conservation refers to maintaining the productivity of agricultural land by control of the erosion of soil by wind or water. Soil conservation practices use the land according to its needs and capabilities. Erosion is any process by which soil is transported from one place to another. At naturally occurring rates, land typically loses about one inch (2.5 cm) of topsoil in 100-250 years. A tol…
Solar Flare
A solar flare is a sudden, localized release of energy in the sun's outer atmosphere. This energy, in the form of radiation, is distributed throughout the electromagnetic spectrum, allowing flares to be seen at many different wavelengths, from the x ray to the radio regions. A solar flare erupting from the chromosphere of the sun. NASA/Science Photo Library/Photo Researchers, Inc. Repro…
Solar Illumination: Seasonal and Diurnal Patterns
Earth rotates about its polar axis as it revolves around the Sun. Earth's polar axis is tilted 23.5° to the orbital plane (ecliptic plane). Combinations of rotation, revolution, and tilt of the polar axis result in differential illumination and changing illumination patterns on Earth. These changing patterns of illumination result in differential heating of Earth's surface tha…
Solar Prominence
Solar prominences are large, glowing clouds of gas suspended in magnetic field loops above the Sun's photosphere. Although impossible to see in white light (the brilliance of the photosphere blots them out), they are easily visible in hydrogen alpha images (pictures taken in light emitted by hydrogen atoms, the principal constituent of the Sun). Prominences have been observed during eclipse…
Solstice
The term solstice refers to the two dates of the year on which the Sun reaches its northernmost and southernmost declinations (declination is the celestial equivalent of latitude). During the spring we frequently hear someone remark that "the days are getting longer," or during the fall that they are getting shorter. This phenomenon occurs because Earth's rotational axis is ti…
Solubility - Common Measuring Units, Effect Of Temperature On Solubility, Effect Of Chemical Bonding On Solubility
Solubility in the general sense refers to the property of being soluble—being able to dissolve, usually in a liquid. Chemists, however, use the word solubility to also mean the maximum amount of a chemical substance that dissolves in a given amount of solvent at a specific temperature. How much sugar could you dissolve in a cup of hot coffee? Certainly one teaspoonful would mix into the liq…
Solution
A solution is a homogenous (uniform throughout) mixture, on a molecular level, of two or more substances. It is formed when one or more substances are dissolved in one or more other substances. The scientific nature of solutions is a relatively recent discovery, though solutions in one form or another have been used by people throughout history. The substances (solids, liquids, or gasses) in a sol…
Solution of Equation - Methods For Solving Simple Equations, Solving More Complex Equations, Solving Multivariable Equations, Solving Second Degree And Higher Equations
The solution of an equation is the set of all values which, when substituted for unknowns, make an equation true. For equations having one unknown, raised to a single power, two fundamental rules of algebra, including the additive property and the multiplicative property, are used to determine its solutions. Solutions for equations with multiple unknown variables are found by using the principles …
Song Birds
Song birds are any birds that sing musically, almost all of which are in the suborder Oscines of the order Passeriformes, or perching birds. Passeriform birds have feet adapted for gripping branches, plant stems, and similar perches, and they comprise about one-third of living bird families, and one-half of the species. A major function of singing in birds is to proclaim the location and limits of…
Sonoluminescence
Sonoluminescence is the emission of light from bubbles of air trapped in water which contains intense sound waves. Hypothesized in 1933 by Reinhardt Mecke of the University of Heidelberg, from the observation that intense sound from military sonar systems could catalyze chemical reactions in water, it was first observed in 1934 by H. Frenzel and H. Schultes at the University of Cologne. Modern exp…
The Sophists - Sophistic Speeches, Pedagogy, Doctrines, Historiography, Bibliography
Sophistic speeches were famous in antiquity for their rhetorical style and their moral and philosophical content. Prodicus' "Hercules at the Crossroads," (see Xenophon, Memorabilia, II.i.21–34) depicts a young Hercules at the brink of manhood choosing between a life of virtue and one of vice. Though the life of vice appears easy at first and the life of virtue difficult…
Sorghum
Sorghum (genus Sorghum) refers to various species of grasses (family Poaceae) that are cultivated as food crops. Because the relationships among the various species and their hybrids are highly complex and not well understood, the cultivated grain sorghums are usually named as Sorghum bicolor. Sorghum is a tropical grass, well adapted to high productivity in a hot and dry climatic regime, and wate…
Sound Waves - Sound Wave Interactions And The Doppler Effect, Speed Of Sound
Sound waves are pressure waves that travel through Earth's crust, water bodies, and atmosphere Sound waves induce vibration in a body (e.g., the tympanic membrane of the ear) or are produced as a result of vibration of that body. Sound waves can be detected and interpreted by instrumentation (e.g., by a seismograph), or by variety of pressure sensitive organs in living beings (e.g., the lat…
South America - The Highlands And Plateaus, The Andes, The Amazon Basin, The Climate, Venezuela, Ecuador - The continent, The countries, Uruguay
The South American continent stretches from about 10° above the equator to almost 60° below it, encompassing an area of about 7 million sq mi (18 million sq km). It is divided into ten countries. The continent can be divided into three main regions with distinct environmental and geological qualities: the highlands and plateaus of the east, which are the oldest geological feature in …
Sovereignty - Early Concepts, Early Modern Views: Absolutism, Early Modern Views: Popular Sovereignty, Later Developments
Sovereignty refers to the supreme and ultimate source of authority that exists within any political unit or association. A sovereign power is deemed independent of all other authorities and it possesses no rivals within its jurisdiction. Thus, sovereignty has internal and external dimensions. Internally, it connotes the superior and final power to determine who shall rule and how rule shall occur.…
Soybean
The soybean (Glycine max) is a domesticated species in the pea family (Fabaceae). Like other cultivated species in this family, soybean has symbiotic Rhizobium bacteria growing in nodules on its roots. These bacteria fix atmospheric nitrogen gas into ammonia and allow the crop to grow with relatively little additional fertilization of this key nutrient. Soybean is an annual, dicotyledonous plant. …
Space
Space is the three-dimensional extension in which all things exist and move. We intuitively feel that we live in an unchanging space. In this space, the height of a tree or the length of a table is exactly the same for everybody. Einstein's special theory of relativity tells us that this intuitive feeling is really an illusion. Neither space nor time is the same for two people moving relati…
Space Probe - Probe Flight And Supporting Facilities, Design And Classification, Space Probe Families, Recent And Future Space Probes
A space probe is any uncrewed, instrument-carrying spacecraft designed to travel to an extraterrestrial environment beyond Earth orbit. The first recorded mention of a possibility of a true space probe dates to 1919, when United States physicist and rocketry pioneer Robert Goddard (1882–1945) suggested that a flash from an explosion produced by a rocket on the Moon's surface could be…
Space Shuttle - Mission Of The Space Shuttle, The Orbiter, Propulsion Systems, Orbital Maneuvers, Orbital Activities - Structure of the STS
The space shuttle is a reusable spacecraft that takes off like a rocket, orbits the Earth like a satellite, and then lands like a glider. The space shuttle has been essential to the repair and maintenance of the Hubble Space Telescope and to construction of the International Space Station; it has also been used for a wide variety of other military, scientific, and commercial missions. It is not ca…
Manned Spacecraft - Ongoing Debate: Crewed Vs. Uncrewed Flight, Overview, One-person Crewed Spacecraft, Two- And Three-person Spacecraft - Technical requirements of crewed spacecraft
Manned spacecraft are vehicles that can transport human beings outside the Earth's atmosphere. The word "manned," though still used occasionally by the United States National Aeronautics and Space Administration (NASA), is often replaced today in discussions of space travel by the word "crewed," in recognition of the fact that women also travel in space. In its e…
Sparrows and Buntings - Biology Of Sparrows And Buntings, Sparrows And Buntings In North America, Sparrows And Buntings Elsewhere
The typical sparrows, buntings, and their allies are 281 species of birds that comprise the subfamily Emberizinae, family Emberizidae. The emberizid sparrows and buntings occur in a great variety of habitats, and are widely distributed, occurring on all of the habitable continents except for Southeast Asia and Australia. The greatest diversity of species, however, occurs in the Americas. The phylo…
Spectroscope - Instruments for viewing spectra
A spectroscope is an instrument used to observe the atomic spectrum of a given material. Because atoms can absorb or emit radiation only at certain specific wavelengths defined by electron transitions, the spectrum of each type of atom is directly related to its structure. There are two classifications of atomic spectra: absorption and emission. An absorption spectrum is produced when light passes…