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Bell Jar
A bell jar is a glass jar, similar in shape to a bell (i.e. in its best-known form it is open at the bottom, while its top and sides together are a single piece), and can be manufactured from a variety of materials (ranging from glass to different types of metals). Bell jars are often used in laboratories to form and contain a vacuum. It is a common science apparatus used in experiments. Bell jars have a limited ability to create strong vacuums; vacuum chambers are available when higher performance is needed. They have been used to demonstrate the effect of vacuum on sound propagation. In addition to their scientific applications, bell jars may also serve as display cases or transparent dust covers. In these situations the bell jar is not usually placed under vacuum. Vacuum A vacuum bell jar is placed on a base which is vented to a hose fitting, that can be connected via a hose to a vacuum pump. A vacuum is formed by pumping the air out of the bell jar. The lower edge of a va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell (instrument)
A bell is a directly struck idiophone percussion instrument. Most bells have the shape of a hollow cup that when struck vibrates in a single strong strike tone, with its sides forming an efficient resonator. The strike may be made by an internal "clapper" or "uvula", an external hammer, or—in small bells—by a small loose sphere enclosed within the body of the bell (jingle bell). Bells are usually cast from bell metal (a type of bronze) for its resonant properties, but can also be made from other hard materials. This depends on the function. Some small bells such as ornamental bells or cowbells can be made from cast or pressed metal, glass or ceramic, but large bells such as a church, clock and tower bells are normally cast from bell metal. Bells intended to be heard over a wide area can range from a single bell hung in a turret or bell-gable, to a musical ensemble such as an English ring of bells, a carillon or a Russian zvon which are tuned to a common scale and instal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science View
Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence for scientific reasoning is tens of thousands of years old. The earliest written records in the history of science come from Ancient Egypt and Mesopotamia in around 3000 to 1200 BCE. Their contributions to mathematics, astronomy, and medicine entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages, but was preserved in the Muslim world during the Islamic Golden Age and later by the efforts of Byzantine Greek scholars who brought Greek man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ray Bradbury Short Fiction Bibliography
This is a chronological list of short fiction by American writer Ray Bradbury Ray Douglas Bradbury (; August 22, 1920June 5, 2012) was an American author and screenwriter. One of the most celebrated 20th-century American writers, he worked in a variety of modes, including fantasy, science fiction, horror, mystery, and r .... Only original works are listed, along with their first publication. Several stories exist in one or more revised versions, sometimes under different titles. 1930s 1938 1939 1940s 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950s 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960s 1960 1962 1964 Heavy Set 1965 References The primary source of information for this list is: :Eller, Jonathan R., and William F. Touponce. Ray Bradbury: The Life of Fiction. Kent State University Press, 2004. Additionally, the Internet Speculative Fiction Database (ISFDB) has provided valuable infor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloche (agriculture)
In agriculture and gardening, a cloche (from French, ''cloche'' for "bell") is a covering for protecting plants from cold temperatures. The original form of a cloche is a bell-shaped glass cover that is placed over an individual plant; modern cloches are usually made from plastic. The use of cloches is traced back to market gardens in 19th century France, where entire fields of plants would be protected with cloches. In commercial growing, cloches have largely been replaced by row cover, and nowadays are mainly found in smaller gardens. History Parisian market gardens in the 1800s used 18-inch diameter bell-shaped glass jars (cloches) to protect plants in cold weather. They were used to protect everything from young seedlings to mature plants. Notched wooden sticks were used to prop up and vent the jars on sunny days, and were placed back down on the soil before nightfall. "Chase barn cloches", introduced in the early twentieth century by Major L.H. Chase, are constructed wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxidermy
Taxidermy is the art of preserving an animal's body via mounting (over an armature) or stuffing, for the purpose of display or study. Animals are often, but not always, portrayed in a lifelike state. The word ''taxidermy'' describes the process of preserving the animal, but the word is also used to describe the end product, which are called taxidermy mounts or referred to simply as "taxidermy". The word ''taxidermy'' is derived from the Greek words ''taxis'' and ''derma''. ''Taxis'' means "arrangement", and ''derma'' means "skin" (the dermis). The word ''taxidermy'' translates to "arrangement of skin". Taxidermy is practiced primarily on vertebrates (mammals, birds, fish, reptiles, and less commonly on amphibians) but can also be done to larger insects and arachnids under some circumstances. Taxidermy takes on a number of forms and purposes including hunting trophies and natural history museum displays. Museums use taxidermy as a method to record species, including those ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Victorian Period
In the history of the United Kingdom and the British Empire, the Victorian era was the period of Queen Victoria's reign, from 20 June 1837 until her death on 22 January 1901. The era followed the Georgian period and preceded the Edwardian period, and its later half overlaps with the first part of the '' Belle Époque'' era of Continental Europe. There was a strong religious drive for higher moral standards led by the nonconformist churches, such as the Methodists and the evangelical wing of the established Church of England. Ideologically, the Victorian era witnessed resistance to the rationalism that defined the Georgian period, and an increasing turn towards romanticism and even mysticism in religion, social values, and arts. This era saw a staggering amount of technological innovations that proved key to Britain's power and prosperity. Doctors started moving away from tradition and mysticism towards a science-based approach; medicine advanced thanks to the adoption o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass Terrarium And Succulent (Unsplash)
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of the molten form; some glasses such as volcanic glass are naturally occurring. The most familiar, and historically the oldest, types of manufactured glass are "silicate glasses" based on the chemical compound silica (silicon dioxide, or quartz), the primary constituent of sand. Soda–lime glass, containing around 70% silica, accounts for around 90% of manufactured glass. The term ''glass'', in popular usage, is often used to refer only to this type of material, although silica-free glasses often have desirable properties for applications in modern communications technology. Some objects, such as drinking glasses and eyeglasses, are so commonly made of silicate-based glass that they are simply called by the name of the material. Despite bei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Round Bottom Flasks
Round-bottom flasks (also called round-bottomed flasks or RB flasks) are types of Laboratory flask, flasks having spherical bottoms used as laboratory glassware, mostly for chemistry, chemical or biochemistry, biochemical work. They are typically made of glass for chemical Chemically inert, inertness; and in modern days, they are usually made of heat-resistant borosilicate glass. There is at least one tubular section known as the ''neck'' with an opening at the tip. Two- or three-necked flasks are common as well. Round bottom flasks come in many sizes, from 5 mL to 20 L, with the sizes usually inscribed on the glass. In pilot plants even larger flasks are encountered. The ends of the necks are usually conical ground glass joints. These are standardized, and can accept any similarly-sized tapered (male) fittings. Ground glass joint, 24/20 is common for 250 mL or larger flasks, while smaller sizes such as 14/20 or 19/22 are used for smaller flasks. Because of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stress Concentration
In solid mechanics, a stress concentration (also called a stress raiser or a stress riser) is a location in an object where the stress is significantly greater than the surrounding region. Stress concentrations occur when there are irregularities in the geometry or material of a structural component that cause an interruption to the flow of stress. This arises from such details as holes, grooves, notches and fillets. Stress concentrations may also occur from accidental damage such as nicks and scratches. The degree of concentration of a discontinuity under typically tensile loads can be expressed as a non-dimensional stress concentration factor K_t, which is the ratio of the highest stress to the nominal far field stress. For a circular hole in an infinite plate, K_t = 3. The stress concentration factor should not be confused with the stress intensity factor, which is used to define the effect of a crack on the stresses in the region around a crack tip. For ductile materials ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scuba Set
A scuba set, originally just scuba, is any breathing apparatus that is entirely carried by an underwater diver and provides the diver with breathing gas at the ambient pressure. ''Scuba'' is an anacronym for self-contained underwater breathing apparatus. Although strictly speaking the scuba set is only the diving equipment that is required for providing breathing gas to the diver, general usage includes the harness by which it is carried, and those accessories which are integral parts of the harness and breathing apparatus assembly, such as a jacket or wing style buoyancy compensator and instruments mounted in a combined housing with the pressure gauge, and in the looser sense, it has been used to refer to all the diving equipment used by the scuba diver, though this would more commonly and accurately be termed scuba equipment or scuba gear. Scuba is overwhelmingly the most common underwater breathing system used by recreational divers and is also used in professional diving whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Philosophy
Natural philosophy or philosophy of nature (from Latin ''philosophia naturalis'') is the philosophical study of physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ..., that is, nature and the physical universe. It was dominant before the development of modern science. From the ancient world (at least since Aristotle) until the 19th century, ''natural philosophy'' was the common term for the study of physics (nature), a broad term that included botany, zoology, anthropology, and chemistry as well as what we now call physics. It was in the 19th century that the concept of science received its modern shape, with different subjects within science emerging, such as astronomy, biology, and physics. Institutions and communities devoted to science were founded. Isaac Newton's book ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
An Experiment On A Bird In The Air Pump
''An Experiment on a Bird in the Air Pump'' is a 1768 oil-on-canvas painting by Joseph Wright of Derby, one of a number of candlelit scenes that Wright painted during the 1760s. The painting departed from convention of the time by depicting a scientific subject in the reverential manner formerly reserved for scenes of historical or religious significance. Wright was intimately involved in depicting the Industrial Revolution and the scientific advances of the Enlightenment. While his paintings were recognized as exceptional by his contemporaries, his provincial status and choice of subjects meant the style was never widely imitated. The picture has been owned by the National Gallery in London since 1863 and is regarded as a masterpiece of British art. The painting depicts a natural philosopher, a forerunner of the modern scientist, recreating one of Robert Boyle's air pump experiments, in which a bird is deprived of air, before a varied group of onlookers. The group exhibits a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
