Research Results For 'Plastic'

ARTIFICIAL FLOWERS

Artificial flowers are imitations of real flowers, made of various materials. These are not a modern invention. The Romans excelled in the art of imitating flowers in wax, and in this branch of the art attained a high degree of perfection. The Egyptian artificial flowers were made of thin plates of horn stained in different colours, sometimes also of leaves of copper gilt or silvered over. In modern times the Italians were the first to acquire celebrity for the skill and taste they displayed in this manufacture, but they are now far surpassed by English and French manufacturers, but more especially by the latter. During the Victorian period cambric, muslin, satin, velvet, and other woven fabrics, feathers, india-rubber, blown glass, mother of pearl, brass, etc were all employed in making artificial flowers, later silk and plastic were more commonly used, and good results may be had from dyed wood.
Research Artificial Flowers

AUGER

An auger is an instrument used for boring holes in wood, or other soft substances. It consists of a wooden or plastic handle and a steel shank terminated in a steel bit at the bottom.
Research Auger

BEAKER

A beaker was, during the middle-ages and until the 20th century, a large-mouthed, handleless drinking vessel. During the 20th century the term came to be applied to a metal, or usually plastic, drinking vessel, again without handles - thus differentiating it from the glass tumbler. In archaeology, the term beaker may be applied to a type of handless pottery drinking vessel characteristic of the peoples of early bronze age western Europe.
Research Beaker

BICYCLE

A bicycle is a two wheeled vehicle driven by the riders feet pushing on cranks or pedals. A common misconception is that the earliest form of bicycle was the dandy-horse, which was pushed along by the rider's feet. However, while both the dandy-horse and the later bicycle are both velocipedes, the dandy-horse is not propelled by cranks.

The first bicycle was introduced to England from France in 1868, and comprised two solid wheels of equal size fitted to a frame, much like a modern bicycle in appearance, with a saddle fitted in the centre and propelled by cranks attached to the front wheel. This vehicle provided such a bumpy ride to the rider that it became popularly known as 'the bone-shaker'. Later came the Penny-Farthing with pedals fixed to the large front wheel which was made large to achieve high speeds. Later still, around 1895, came the safety bicycle with pedals driving the rear wheel by way of a chain, and the rider sitting upon a saddle set back from the front wheel so as to reduce the chances of falling forwards over the handlebars, from this developed the Raleigh bicycle design of 1900 which forms the basis of the modern bicycle. In 1888 the two-person tandem bicycle was invented.

In 1906 it was reported that speeds of 50 mph were attained on a bicycle. Around the same time, slightly earlier, the motorised bicycle (motorcycle or motorbike) was invented.

A typical bicycle is comprised of several parts. The principal and essential being: the frame, front forks, wheels, pedals, saddle, handlebars, chain and brakes. The largest part of the bicycle is the frame, and these vary in design depending upon the specialised intention of the bicycle.

A frame for a BMX bicycle being small, heavily braced and made of aluminium. The frame for BMX xyxling needs to be strong so as to endure the stresses of the bumpy ride, and the saddle low as competitors never sit down during a competition and as such they need space to sprint and jump with ease.

Cross-Country cycle frames are generally made of aluminium and carbon-fibre so as to be light weight. They are relatively small frames to allow quick and easy mounting and dismounting off road, and strong to endure off-road bumpy conditions. The smaller frames are often compensated for by having a longer seat post to allow a normal height saddle position.

The cycle speedway bicycle frame is designed primarily for strength, and as such is typically made from steel or aluminium.

Road racing bicycle frames are designed to be light and stiff. Traditionally they ewre made of steel, but by the start of the 21st century carbon fibre was being used for the more expensive models as this offered the same stiffness at reduced weight. The design of the tubes also developed over time, tubes becoming of a larger diameter, but thinner walls, to allow the same stiffness with reduced weight.

Bicycles are fitted with various types of brake, the most popular being the calliper, cantilever, hydraulic or disc and the V brake. The most common form of brake found on leisure bicycles, is that form used also on road racing bicycles. The calliper brake. Calliper brakes are a very efficient means of rim braking and basically comprise two blocks of rubber or plastic which are squeezed onto the wheel rim when the brake lever is squeezed by the ride.

Cantilever brakes operate on the same principal as calliper brakes, but are of a slightly different design at the wheel end, offering increased clearance between the tyre and the brake pads and as such are frequently employed for cyclo-cross bicycles and mountain bikes.

The most efficient form of rim brake is the V brake. The V brake also offers the most clearance of any rim braking system, and is most often found on mountain bikes.

Hydraulic or disc brakes are the most efficient and powerful form of bicycle brake. They use the wheel hub to brake, rather than the rim. Disc brakes offer the most clearance, and as such are used on mountain bikes, but are also expensive to fit and maintain.

Bicycle wheels are generally of one of three types. The most common and traitional bicycle wheel is the spoked wheel, comprising a rim connected to the central bub by a series of thin metal rods known as spokes. Spoked wheels are light in weight. Less common than spoked wheels, but offering greater strength and durability at the expense of weight are mag wheels which comprise a rim attached to the hub by a few, thick solid plastic bars. Solid wheels, also known as disc wheels, are made from composite material or carbon fibre are very strong, stiff, aerodynamic and very expensive. They are rarely used except as rear wheels in time-trialing and track racing.
Research Bicycle
More pictures of Bicycle

BOBBIN

A bobbin is a reel or other similar contrivance for holding thread. It is often a cylindrical piece of wood or plastic with a head, on which thread is wound for making lace; or a spool with a head at one or both ends, intended to have thread or yarn wound on it, and used in spinning machinery (when it is slipped on a spindle and revolves therewith) and in sewing-machines (applied within the shuttle).
Research Bobbin

COMB

A comb is an instrument with teeth, formerly made of tortoise-shell, ivory, horn, wood, bone or metal and now most often made from plastic, used for dressing the hair, and by women for keeping the hair in its place when dressed. Combs have been used from the earliest times by all races of people.
Research Comb

CORGI

Research Corgi

GLACIER

Glaciers are icy masses of great bulk, harder than snow, yet not exactly like common ice, which cover the summits and sides of mountains above the snow-line. They are found in Switzerland, Scandinavia, the Andes, etc.

They extend down into the valleys often far below the snow-line, and bear a considerable resemblance to a frozen torrent. They take their origin in the higher valleys, where they are formed by the congelation and compression of masses of snow in that condition called by French writers neve, by German authors, firn.

The ice of glaciers differs from that produced by the freezing of still water, and is composed of thin layers filled with air-bubbles. It is likewise more brittle and less transparent. The glaciers are continually moving downwards, and not unfrequently reach the borders of cultivation. The rate at which a glacier moves generally varies from 45 to 60 cm in twenty-four hours.

At its lower end it is generally very steep and inaccessible. In its middle course it resembles a frozen stream
with an undulating surface, broken up by fissures or crevasses. As it descends it experiences a gradual diminution from the action of the sun and rain, and from the heat of the earth. Hence a phenomenon universally attendant on glaciers - the issue of a stream of ice-cold turbid water from their lower extremity. The descent of glaciers is shown by changes in the position of masses of rock at their sides and on their surface. A remarkable glacier phenomenon is that of moraines, as they are called, consisting of accumulations of stones and detritus piled up on the sides of the glacier, or scattered along the surface. They are composed of fragments of rock detached by the action of frost and other causes.

The fissures or crevasses by which glaciers are traversed are sometimes more than 30 meters in depth, and from being often covered with snow are exceedingly dangerous to travellers. One of the most famous glaciers of the Alps is the Mer de Glace, belonging to Mont Blanc, in the valley of Chamouni, about 1740 meters above sea level. It is more especially, however, in the chain of Monte Rosa that the phenomena of glaciers are exhibited in their greatest sublimity, as also in their most interesting phases from a scientific point of view.

Glaciers exist in all zones in which mountains rise above the snow-line. Those of Norway are well known, and they abound in Iceland and Spitzbergen. Hooker and other travellers gave accounts of those of the Himalaya. They are conspicuous on the Andes, while the Southern Alps of New Zealand rival in this respect the Alpine regions of Switzerland.

The problem of the descent of the glaciers is of extraordinary interest, and various theories have been put forward to account for it. It was shown by Professor Forbes, of Edinburgh, that a glacier moves very much like a river; the middle and upper parts faster than the sides and the bottom; and he showed that glacier motion was analogous to the way in which a mass of thick mortar or a quantity of pitch flows down in an inclined trough. His theory is known as the viscous theory of glaciers, which presupposes that ice is a plastic body, and this plasticity has been satisfactorily explained by Professor James Thomson of Glasgow by the phenomenon of the melting and refreezing of ice.

Water, he discovered, when subjected to pressure, freezes at a lower temperature than when the pressure is removed. Consequently when ice is subjected to pressure it melts; if it is relieved of pressure the water again solidifies. Therefore if two pieces of ice are pressed together, they tend to relieve themselves by melting at their points of contact, and the water thus produced immediately solidifies on its escape. If ice is strained in any way it similarly relieves itself at the strained parts, and a similar regelation follows. This, when applied to the glaciers, gives a complete explanation of their plasticity. Pressed downwards by the vast superincumbent mass, the ice gradually yields. Melting and re-freezing takes place at some parts, at others the gradual yielding at strained points goes on. In the latter process there is no visible melting, but there is the gradual yielding from point to point to the pressure above, and there is the transference relatively to each other of the molecules that constitute the, at first sight, solid mass. If, however, at certain points the strain is intense, the ice becomes extremely brittle. The latter fact disposes of Tyndall's objection to Forbes' theory, which was based on the fact that crevasses proved the brittleness, and not the viscosity of ice.
Research Glacier

GLOBE

A globe is a sphere, a round solid body, which may be conceived to be generated by the revolution of a semicircle about its diameter. An artificial globe, in geography and astronomy, is a globe of metal, plaster, paper, pasteboard, plastic etc, on the surface of which is drawn a map, or representation of either the earth or the heavens, with the several circles which are conceived upon them, the former being called the terrestrial globe, and the latter the celestial globe. In the terrestrial globe the wire on which it turns represents the earth's axis, the extremities of it representing the poles. The brazen meridian is a vertical circle in which the
artificial globe turns, divided into 360 degrees, each degree being divided into minutes and seconds. The brass meridian receives the ends of the axis on which the globe revolves. At right angles to this, and consequently horizontal, is a broad ring of wood or brass representing the horizon; that is, the true horizon of the earth which lies in a plane containing the earth's centre. The horizon and brass meridian are connected with the stand on which the whole is supported. On the surface of the globe, as on other maps, are marked parallels of latitude, meridians, etc. On a globe of some size the meridians are drawn through every 15" of the equator, each answering to an hour's difference of time between two places. Hence they are called the hour circles. A number of problems or questions, many of them more curious than useful, may be solved by means of a terrestrial globe. Among the most important are such as to find the latitude and longitude of a place, the difference of time between two places, the time of the sun's rising and setting for a given day at a given place, etc.

IVORY

Ivory is an opaque, creamy white, hard, fine-grained, modified dentin that composes the upper incisor teeth of an elephant. Ivory is composed of curved layers of dentine alternating in shade, that intersect one another; the resulting lozenge-shaped structure is elastic and finely grained. The layers of a tusk are deposited from the central pulp, so that the innermost layer is the newest. Most commercial elephant ivory is obtained from the tusks of the African elephant, mainly from eastern and central Africa. (Most of the ivory of the western half of Africa is hard, whereas that from the eastern half is soft. Hard ivory is glassier in texture, harder to cut and more likely to crack than soft ivory.)
Fossil ivory, called odontolite, is a blue variety that is found in small quantities in the frozen soil of northern Siberia. Odontolite was produced by the mammoths of the Pleistocene geological epoch; its blue colour results from saturation by metallic salts. Carved ivory has been used for decorative purposes since the time of the ancient Egyptians. Small pieces of ivory are used for high-quality furniture inlays, chess pieces, and small jewellery. Larger pieces of ivory sometimes have been used in the manufacture of billiard balls, piano keys, and toilet articles.
During the late 1980s, as Africa's elephant herds declined, environmentalists led a world-wide effort to shut down the ivory trade; in 1989 the USA and the European Union banned all ivory imports. Tusks of several other animals such as hippopotamuses, narwhals, sperm whales, and walruses are commonly called ivory and have similar physical properties, and many plastic substitutes for ivory have been developed. Several ivory-like vegetable parts are also used in imitation of ivory; the ivory palm, for example, produces large, white, hard seeds, called ivory nuts, the endosperm of which is commonly known as vegetable ivory. In painting, ivory is a delicate colour deeper in tone than off-white, but not so deep as cream.
Research Ivory

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