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 brakepads 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
The Budyonny is a Russian breed of sporting horse developed during the 1920s and named after Marshal Budyonny, a Soviet cavalry commander of the Russian Revolution. The Budyonny stands 16 hands high and is mostly chestnut, but can also be grey, brown, bay or black in colour and exhibits a free action, very good gallop and an athletic jump, but are not so fast as the Thoroughbred. Research Budyonny
Flea-beetles are a group of leaf beetles (Chrysomelidae) with stout hind femora that enable them to jump long distances. They are a significant pest as hibernating beetles often emerge in the spring and may destroy an entire crop. Research Flea-Beetle
The Ibizan hound is a breed of dog, possibly descended from greyhound-like dogs of pre-Christian Egypt, developed in more recent centuries on the island of Ibiza. It became a strong, hardy breed, able to hunt with speed and skill, to jump unusually well, and to withstand hardships. Its keen eyesight makes it good for standing watch as well as for coursing game. The Ibizan has a long, narrow head and muzzle; small, yellowish-brown eyes; large, mobile ears; and long, slightly arched neck. The back is horizontal, the legs long, and the tail long and somewhat curved. Its weight ranges from 19 to 23 kg; average height is from 57 to 70 cm. The coat is generally short and lies flat, but there is also a wire-haired variety, and the colour may be white, red, yellowish red, or combinations of these. The breed is easy to train and affectionate. Research Ibizan Hound
Kangaroo is the name of any marsupial of the family Macropodidae found in Australia, Tasmania, and New Guinea.
Kangaroos are plant-eaters and most live in groups. They are adapted to hopping, the vast majority of species having very large back legs and feet compared with the small forelimbs. The larger types can jump nine metres in a single bound. Most are nocturnal. Species vary from small rat kangaroos, only 30 centimetres long, through the medium-sized wallabies, to the large red and great grey kangaroos, which are the largest living marsupials. These may be 1.8 metres long with 1.1 metres tails. In New Guinea and North Queensland, tree kangaroos (Dendrolagus) occur. These have comparatively short hind limbs. The great grey kangaroo Macropus giganteus produces a single young (called a 'Joey') about two centimetres long after a very short gestation, usually in early summer. At birth the young kangaroo is too young even to suck. It remains in its mother's pouch, attached to a nipple which squirts milk into its mouth at intervals. It stays in the pouch, with excursions as it matures, for about 280 days. Research Kangaroo
Jesse James Cleveland Owens was an American athlete. He was born in 1913 at Danville, Alabama and died in 1980. In 1935 he equalled or broke six world records in 45 minutes, and in 1936 won four gold medals (100 and 200 metres, long jump, and 4 x 100 metres relay) at the Olympic Games in Berlin. The success in Berlin of Owens, as a black man, outraged Hitler, who was conspicuously absent when Owens's medals were presented. Research Jesse Owens
In Greek mythology, Talos was a bronze man given to Europa by Zeus to guard Crete. He would clutch people to his breast and jump into a fire so that they were burnt alive. When the Argonauts in their wanderings came to Crete, and he resisted their landing, Medea killed him.
In Greek mythology, Talos was a nephew of Daedalus, the inventor. Talos was credited with the invention of the saw, compasses, the potters' wheel and other tools. His skill aroused the envy of Daedalus who killed him. Research Talos
The Irvin-GQ LLP Mk 1 is a British low level, static-line operated parachute used by British armed forces for fully equipped airborne troop mass tactical parachute assaults from jump heights as low as 250 feet (76 meters). The Irvin-GQ LLP Mk 1 can cope with a suspended weight of 160 kg and provides a descent speed of between 5 and 6 metres per second depending upon the suspended weight. The Irvin-GQ LLP Mk 1 has an assembly weight of 18.5 kg. Research Irvin-GQ LLP Mk 1
The Faraday cage is an earthed metallic wire or gauze screen enclosing electrical equipment to shield it from the influence of external electric fields. The principle, put forward by Michael Faraday, is that within a conductor there is no charge, and this has been proved correct. The principle is used to make metal jump suits to be worn by electrical engineers working on high tension electricity cables. Research Faraday Cage
Indexing is the process of producing an index. An index is a sorted structure of keys - perhaps titles - and the position of the related record. In a printed book, an index is usually an alphabetically sorted list of key words with the page numbers where the key word occurs. In computing, the principle is the same. A database may contain thousands of records. Searching the database sequentially for a specific record is very slow, so an index is often used. The index file contains key data, perhaps a stock code number or name, together with the position of the associated record. A computer system may then search the sorted index very much more quickly for the required key and having found it, jump to the specified record or position within the main datafile - assuming a random access file. A very popular indexing method used in computer files is the 'B-Tree' or 'balanced multiway tree' in which a search follows a binary pattern, starting with a single root and branching until the desired key is located. This
saves the developed from having to code their own binary search on a sequentially arranged, sorted index file. Research Indexing
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Bicycle
