Science & Philosophy: Ballistic galvanometer to Big–bang theory
Balloon - Balloons and the exploration of the unknown
A balloon is a nonsteerable aircraft consisting of a thin envelope inflated with any gas lighter than the surrounding air. The balloon rises from the ground similar to a gas bubble in a glass of soda. The physical principle underlying this ability to ascend is Archimedes' law, according to which any immersed body is pushed upward by a force equal to the weight of the displaced fluid. If thi…
Bandicoots
Australian wildlife holds many surprises, but few as intriguing as the widely distributed bandicoots. These small, rabbit-sized marsupials have a thick set body, short limbs, a pointed muzzle, short neck and short hairy tail. Their teeth are similar to those of insect- and flesh-eating mammals, but their hind feet resemble those of kangaroos and possums. The hindfeet are not only considerably long…
Bar Code
Almost everyone is familiar with the striped bars found on grocery and retail store items. These are bar codes, or more specifically, the Universal Product Code (UPC). UPC codes first appeared in stores in 1973 and have since revolutionized the sales industry. The UPC code consists of ten pairs of thick and thin vertical bars that represent the manufacturer's identity, The parts of the …
Barbarism and Civilization - Friedrich Engels: Barbarism And Civilization, Herodotus And The Barbarians, Toynbee's Rhythm Of History
Barbarism and civilization are salt and pepper concepts that are inextricably interlinked. In the Western world, "barbarism" is derived from the classical Greek word barbaros (barbarian) that referred originally to foreigners who did not speak Greek. In the modern world, barbarism carries a negative connotation of unrefined and savage. "Civilization" is derived from the…
Barberry
Barberries are about 600 species of plants in the genus Berberis, family Berberidaceae, occurring throughout the Northern Hemisphere and South America. Most species of barberry are shrubs or small trees, and many of these have persistent, evergreen leaves. The flowers are small, arranged in clusters, and insect pollinated. The fruits of barberries are multiple-seeded berries. Barberry hybrids are …
Barbets
Barbets are about 76 species of medium-sized birds, divided among 13 genera. These comprise the family Capitonidae, in the order Piciformes, which also contains the woodpeckers, toucans, and their allies. Barbets are birds of tropical forests, occurring in Central and South America, Africa, and Asia as far south as Indonesia. However, none of the species of barbets occur in more than one continent…
Barbiturates - Recommended Dosage, Precautions, Side Effects, Interactions - Description, Special conditions, Allergies, Pregnancy, Breastfeeding, Other medical conditions, Use of certain medicines
Barbiturates are in the group of medicines known as central nervous system (CNS) depressants. Also known as sedative-hypnotic drugs, barbiturates make people very relaxed, calm, and sleepy. These drugs are sometimes used to help patients relax before surgery. Some may also be used to control seizures (convulsions). Although barbiturates have been used to treat nervousness and sleep problems, they …
Bariatrics - The Problem Of Obesity, The Tools Of Bariatric Medicine, A Multiple Approach To Weight Management
Recent reports estimate that the proportion of individuals who are overweight in the United States surpasses 50% of the adult population. Such a staggering statistic has associated with it profound ramifications. Excess weight is a major contributor to serious health conditions that affect millions of people and can result in early death. Aside from tangible diseases, obesity is the root of much p…
Barium
Although pure barium is rarely used outside the laboratory, barium's many compounds have a number of practical applications. Perhaps the most familiar is the barium enema. When doctors need to examine a patient's digestive system, a mixture containing barium sulfate is used to coat the inner lining of the intestines. Similarly, to enhance examination of the stomach and esophagus, the…
Barium Sulfate
Barium sulfate occurs in nature as the mineral barite, or baryte, which is mined in Canada and Mexico and, in the United States in Arkansas, Missouri, Georgia, and Nevada. It is also prepared synthetically either by treating a solution of a barium salt with sodium sulfate or as a by-product in the manufacture of hydrogen peroxide. Barium sulfate is used in diagnostic radiology of the digestive sys…
Bark
Bark is a protective, outer tissue that occurs on older stems and roots of woody coniferous and angiosperm plants. Bark is generally considered to occur on the outside of the tissue known as wood, or the water-conducting xylem tissues of woody plants. The inner cells of bark, known as phloem, grow by the division of outer cells in a generative layer called the vascular cambium, located between the…
Barley
Barley is one of the world's major cultivated crops. It is a member of the grass family (Poaceae). In 1999, approximately142 million acres (57.5 million ha) of barley were grown worldwide and the total production was 147.0 million tons of grain (133.6 million tonnes). Harvesting barley with a combine tractor. Photograph by Holt Studios Limited Ltd. Photo Researchers, Inc. Reproduced by…
Barnacles
The rocky shores of most coastlines are liberally dotted with clusters of barnacles (phylum Arthropoda, class Crustacea). Few people take any notice of these animals, despite their common occurrence. Barnacles are exclusively marine animals: some 900 species have been identified worldwide. Many are tiny organisms measuring just a few centimeters in diameter, while others such as the South American…
Barometer - Mercury Barometers, Aneroid Barometer, The Altimeter
A barometer is an instrument for measuring atmospheric pressure. Two kinds of barometers are in common use, a mercury barometer and an aneroid barometer. The first makes use of a long narrow glass tube filled with mercury supported in a container of mercury, and the second makes use of a diaphragm whose size changes as a result of air pressure. The barometer described above is adequate for making …
Barracuda - Predatory Behavior, The Great Barracuda (sphyraena Barracuda), The Pacific Barracuda, Human Fear Of Barracudas
A barracuda is a long, cylindrical, silvery fish. It has two widely separated dorsal fins, in roughly the same location as the two fins on its belly, and a forked tail. The largest species, the great barracuda, seldom grows longer than 6.5 ft (2 m) and is an aggressive fearsome predator of other fish. All barracudas have an underhung jaw that houses long, incredibly sharp teeth; their teeth are co…
Barrier Islands - Barrier Island Origins, Barrier Island Zonation, Can Humans And Barrier Islands Coexist?
A barrier island is a long, thin, sandy stretch of land oriented parallel to the mainland coast, which protects the coast from the full force of powerful storm waves. Between the barrier island and the mainland is a lagoon or bay. Barrier islands are dynamic systems that migrate under the influence of changing sea levels, storms, waves, tides, and longshore currents. Approximately 2,100 barrier is…
Basin
Within the broad field of geology, the term basin can be used to represent a number of features. These include topographic or drainage basins, structural basins, and sedimentary basins. In some cases, a single basin can include aspects of more than one of these types of basins. A topographic, or drainage, basin is a sloping or depressed area from which runoff collects and flows into a channel, str…
Bass
Bass is the common name for a number of popular freshwater and saltwater fish, which include the wide mouth bass, the striped bass, groupers, jewfish, and wreckfish, which are some of the finest sports and food fish in the world. Fish known as bass actually belong to different families and are distributed worldwide in tropical and temperate waters. The freshwater family Centrarchidae includes the …
Basswood
Basswoods are about 30 species of trees in the genus Tilia, in the linden family Tiliaceae. In North America, these trees are generally known as basswoods in forestry, and as lindens in horticulture. Basswoods have simple, long-petioled, coarsely toothed, broadly heart-shaped leaves, arranged alternately on their twigs. The flowers occur in clusters, and emerge from a specialized leaf known as a b…
Bathysphere
Throughout human history, the sea has yielded an abundance of resources for man's existence and provided efficient routes for exploration and transportation. In return, it has exacted a toll in terms of human life and property. The fear and respect that it earned from those who ventured out upon its surface was itself a deterrent to learning more about its mysteries. The physical restrictio…
Bats - Basic Body Plan, Diet, Sensory Systems And Echolocation, Roosting, Reproduction And Social Organization
Bats are one of the most diverse and widely distributed groups of mammals on Earth, second only to rodents in the number of species. More than 900 species of bats have been described. They occur in most terrestrial biomes, except for the high Arctic and all of Antarctica. Bats are the only truly flying mammals, and are distinct from the flying lemurs and flying squirrels, which actually glide. Bat…
Battery - Background, Primary Cells - Moderate energy primary cells, Medium to high energy primary cells, Secondary cells, Moderate energy storage cells
If two metals are immersed in an aqueous solution that can conduct electricity (electrolyte), they will have different tendencies to dissolve in the solution. A difference in voltage arises because one of the metals appears positive or negative relative to the other. The combination of two metals (electrodes) in an aqueous solution for the purpose of producing electrical energy from chemical energ…
Beach Nourishment
Beach nourishment is the artificial process of adding sediment to a beach for recreational and aesthetic purposes, as well as to provide a buffer to coastal erosion. The sand may be dredged from nearby and pumped onto the beach, or transported in from outside areas. It is considered a soft method of stabilizing the shoreline, as opposed to rock and concrete structures meant to capture sand or prot…
Beardworms
Beardworms are slim, wormlike, deep-sea creatures so named for the thick cluster of long, fine, hairlike tentacles projecting from the front of the first section of a three-segmented body. There are approximately 120 species of beardworms, which belong to the phylum Pogonophora-from the Greek pogon, meaning beard, and phoron, meaning bearer. The front section of the beardworm's body, which …
Bears - Grizzly And Other Brown Bears, Polar Bear, American Black Bear, Other Black-colored Bears
Bears are large carnivores of the family Ursidae. They are members of the order Carnivora, which also includes dogs, cats, and seals, although these animals are in different families than bears. All of these carnivores have a pair of modified teeth in the upper and lower jaw, called carnassials, that are used to tear meat into smaller chunks during feeding. Bears are not strictly meat-eaters, howe…
Beauty and Ugliness - Definitions Of Beauty, The Function Of Beauty, Bibliography
Beauty is a vital and central element of human experience. It is associated with pleasure, which influences personal choices and cultural developments. Poets praise it, artists strive to capture it in their works, moralists warn against its deceiving influence, scientists seek to uncover its secrets, and philosophers reflect on its illusive nature. Expressions of the vitality of beauty in its role…
Beavers - The American Beaver, Beavers And The Fur Trade, The Eurasian Beaver, The Mountain Beaver
The true beavers are robust, aquatic herbivores in the family Castoridae, order Rodentia. Many taxonomists believe that two, closely related species of true beavers exist—the American beaver (Castor canadensis) and the Eurasian beaver (C. fiber). Other taxonomists, however, classify these as closely related variants of the same species, under the name Castor fiber. A few other rodents are a…
Bee-Eaters
Bee-eaters are 24 species of birds that make up the family Meropidae. Bee-eaters occur in open habitats and savannas of the south-temperate and tropical zones, ranging through Africa, southern Europe, southern Asia, Southeast Asia, and many Pacific Islands. Species that breed in temperate habitats migrate to the tropics for the winter. Bee-eaters have large, pointed wings and a long tail, usually …
Beech Family (Fagaceae)
The beech family is an important group of flowering plants that includes the beeches, oaks, and sweet chestnuts. Most members of the family are deciduous or evergreen trees or shrubs. The leaves are arranged alternately along branches, are leathery in texture, often strongly ribbed, and have margins that are entire, toothed, or deeply lobed. The flowers are unisexual. Male flowers are usually arra…
Bees - Bee Families, Solitary Bees, Social Bees, Honey Bees, Beekeeping, Killer Bees
Bees belong to the insect order Hymenoptera, which includes wasps and ants. Its name is derived from Greek, meaning "winged membrane," and it is the third largest group of insects with more than a hundred thousand species in the order. Ants and bees play vital roles in agriculture, ants being useful in aerating soil and bees in pollinating plants. Wasps play an important part as pred…
Beet
Beet belongs to the genus Beta in the goosefoot family, Chenopodiaceae. There are several varieties of beet and all are used as food for either animals or humans. Most species of beet are biennial and are harvested after the first growing season when the roots are most nutritious. The wild beet, Beta maritima, is thought to be the species from which cultivated beets (Beta vulgaris), originate. Wil…
Beetles - Varieties Of Beetles, Beetle Anatomy And Physiology, Life Cycle, Defense, Parasitic Beetles, Beetles And Humans
Beetles make up the large, extremely diverse order Coleoptera of the class Insecta, and comprise the largest single group of animals on Earth. There are at least 250,000 species of beetles, compared to the 5,000 known species of mammals. The weevil family of beetles alone contains about 50,000 species, and is the largest family in the animal kingdom. Thus, the order Coleoptera, representing about …
Begonia
Begonias (genus Begonia) are attractive perennial herbs with soft, succulent stems, and white, pink, red, orange, or yellow flowers. Begonias are members of the begonia family, Begoniaceae, order Violales, subclass Dilleniidae, class Magnoliopsida (dicotyledons), division Magnoliophyta (flowering plants). The begonia family consists of five genera and 920 true species, the majority of which belong…
Behavior - Behavior In Plants, Animal Behavior
Behavior is the way that living things respond to their environment. A behavior consists of a response to a stimulus or factor in an individual's internal or external environment. Stimuli include chemicals, heat, light, pressure, and gravity. All living things exhibit behavior. When dust irritates our throats, for example, we respond with coughing behavior. Plants respond with growth behavi…
Behaviorism - Behaviorism (1910–1930), Neobehaviorism (1930–1955), Bibliography
Behaviorism is a theoretical approach in psychology that emphasizes the study of behavior—that is, the outwardly observable reactions to a stimulus of an organism, whether animal or human—rather than the content of the mind or the physiological correlates of behavior. Largely centered in the United States, behaviorism had an early stage (1910–1930) that was dominated by the wo…
Bennettites
The bennettites are an extinct group of gym nosperms—seed-bearing plants whose seeds are exposed to the air, not enclosed in the ovary of a flower. Botanists hypothesize that bennettites are related to the cycads, an extant group of gymnosperms, and paleobotanists believe the bennettites originated from the seed ferns (Pteridospermales) about 220 million years ago during the Triassic period…
Benzoic Acid
In its pure form, benzoic acid exists as white needles or scales with a strong characteristic odor. It melts at 252.3°F (122.4°C), although it may also sublime at temperatures around 212°F (100°C). It dissolves only sparingly in cold water [0.4 g/100 g at 77°F (25°C)], but more completely in hot water [6.8 g/100 g at 203°F (95°C)]. Benzoic ac…