Three wheels on an antique tricycle

A wheel is a circular device that is capable of rotating on its axis, facilitating movement or transportation whilst supporting a load (mass), or performing labour in machines. Mass is a fundamental concept in Physics, roughly corresponding to the Intuitive idea of how much Matter there is in an object A wheel, together with an axle overcomes friction by facilitating motion by rolling. An axle is a central shaft for a rotating Wheel or Gear. In some cases the axle may be fixed in position with a bearing or Bushing Friction is the Force resisting the relative motion of two Surfaces in contact or a surface in contact with a fluid (e Rolling is a combination of Rotation (of a radially symmetric object and translation of that object with respect to a surface (either one or the other moves such that In order for wheels to rotate, a moment needs to be applied to the wheel about its axis, either by way of gravity, or by application of another external force. Common examples are found in transport applications. Transport or transportation is the movement of people and goods from one place to another More generally the term is also used for other circular objects that rotate or turn, such as a Ship's wheel, steering wheel and flywheel. The wheel of a Ship is the modern method of adjusting the angle of the Rudder, in turn changing the direction of the Boat or Ship. A steering wheel (also called a driving wheel or hand wheel) is a type of steering Control in Vehicles and vessels ( Ships and Boats A flywheel is a mechanical device with significant Moment of inertia used as a storage device for Rotational energy.

Etymology

The English word wheel comes from the Proto-Indo-European *k^wek^wlo-,^[1] which was an extended form of the root *k^wel- meaning "to revolve, move around". This is also the root of the Greek κυκλος kuklos, the Sanskrit chakra, and Persian charkh, all meaning "circle" or "wheel",^[2] and also in Lithuanian, sukti means "to rotate". Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly Sanskrit (sa संस्कृता वाक् saṃskṛtā vāk, for short sa संस्कृतम् saṃskṛtam) is a historical Chakra ( Pali: chakka Tibetan: khorlo Malay: cakera is a Sanskrit term meaning Circle or Wheel Lithuanian ( lietuvių kalba) is the official state language of Lithuania and is recognised as one of the official languages of the European Union. The Latin word rota is from the Proto-Indo-European *rotā-, the extended o-grade form of the root *ret- meaning "to roll, revolve". ^[3]

History

A depiction of onager-drawn carts on the Sumerian "battle standard of Ur" (circa 3200 BC)

A spoked wheel on display at The National Museum of Iran, in Tehran. The Onager ( Equus hemionus) is a large Mammal belonging to the horse family and native to the deserts of Syria, Iran, Pakistan Sumer ( Sumerian: sux-Latn [[Ki (earth ki]]-[[EN (cuneiform en]]-'''ĝir15''', Akkadian: Šumeru; possibly Biblical Shinar Ur ( Sumerian:urim; Akkadian: ?) is modern Tell el-Mukayyar, Iraq, and was a city in ancient Sumer. The National Museum of Iran (in Persian: موزه ملي ايران Mūze-ye Millī-ye Irān, or موزه ایران باستان Muze-ye Irân-e Bâstân Tehran (or Teheran) ( Persian: تهران Tehrān) is the capital and largest City of Iran, and the administrative center of The wheel is dated late 2nd millennium BC and was excavated at Choqa Zanbil. Chogha Zanbil (چُغازَنبیل is an ancient Elamite complex in the Khuzestan province of Iran.

The wheel most likely originated in ancient Mesopotamia in the 4th millennium BC. Mesopotamia (from the Greek meaning "land between the rivers" is an area geographically located between the Tigris and Euphrates rivers largely corresponding The wheel reached ancient India with the Indus Valley Civilization in the 3rd millennium BC. This article is about the history of South Asia prior to the Partition of British India in 1947 The Indus Valley Civilization (Mature period 2600&ndash1900 BCE abbreviated IVC, was an ancient Civilization that flourished in the Indus River basin Near the northern side of the Caucasus several graves were found, in which since 3700 BC people had been buried on wagons or carts (both types). The Caucasus ( also referred to as North Caucasus) is a geopolitical region located between Europe Asia & Middle East A wagon (in British English, sometimes waggon) or dray is a heavy four-wheeled Vehicle. "CARTS" redirects here For the transportation system see Capital Area Rural Transportation System, or Chautauqua CARTS. The earliest depiction of what may be a wheeled vehicle (here a wagon—four wheels, two axles), is on the Bronocice pot, a ca. The Bronocice pot is a Ceramic vase incised with the earliest known image of what may be a Wheeled vehicle 3500 BC clay pot excavated in southern Poland,^[4] an area then inhabited by the Proto-Indo-Europeans. Poland (Polska officially the Republic of Poland The Proto-Indo-Europeans (PIE were the speakers of the Proto-Indo-European language, who likely lived around 4000 BC, during the Copper Age and the

The wheel reached Europe and India (the Indus Valley civilization) in the 4th millennium BC. This article is about the history of South Asia prior to the Partition of British India in 1947 The Indus Valley Civilization (Mature period 2600&ndash1900 BCE abbreviated IVC, was an ancient Civilization that flourished in the Indus River basin In China, the wheel is certainly present with the adoption of the chariot in ca. China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National The chariot is the earliest and simplest type of Carriage, used in both peace and war as the chief vehicle of many ancient peoples 1200 BC, and Barbieri-Low (2000) argues for earlier Chinese wheeled vehicles, circa 2000 BC. It is an open question whether there was an independent "invention of the wheel" in Adam Volk. Alternatively, the concept may have made its way there after jumping the Himalayan barrier. It has even been suggested that the introduction of the wheel into China was through Chariot wielding conquerors, possibly connected to inception of the Shang Dynasty (ca. The chariot is the earliest and simplest type of Carriage, used in both peace and war as the chief vehicle of many ancient peoples 1700 BC). ^[5]

Although they did not develop the wheel proper, the Olmec and certain other western hemisphere cultures seem to have approached it, as wheel-like worked stones have been found on objects identified as children's toys dating to about 1500 BC. The Olmec were an ancient Pre-Columbian people living in the Tropical lowlands of south-central Mexico, in what are roughly the modern-day states The Western Hemisphere, also Western hemisphere or western hemisphere, is a geographical term for the half of the Earth that lies West Culture (from the Latin cultura stemming from colere, meaning "to cultivate" generally refers to patterns of human activity and the symbolic In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere CHILD syndrome (or congenital hemidysplasia with ichthyosiform erythroderma and limb defects) is a genetic disorder This article is about playthings For other uses of the term see Toy (disambiguation.

The invention of the wheel thus falls in the late Neolithic, and may be seen in conjunction with the other technological advances that gave rise to the early Bronze Age. The Neolithic (from Greek νεολιθικός — neolithikos from νέος neos, "new" + λίθος lithos The term Bronze Age refers to a period in human cultural development when the most advanced Metalworking (at least in systematic and widespread use included techniques for Note that this implies the passage of several wheel-less millennia even after the invention of agriculture. Agriculture refers to the production of goods through the growing of plants and fungi and the raising of domesticated Animals The study of agriculture Looking back even further, it is of some interest that although paleoanthropologists now date the emergence of anatomically modern humans to ca. Paleoanthropology, which combines the disciplines of Paleontology and Physical anthropology, is the study of ancient humans as found in Fossil hominid 150,000 years ago, 143,000 of those years were "wheel-less". That people with capacities fully equal to our own walked the earth for so long before conceiving of the wheel may be initially surprising, but populations were extremely small through most of this period and the wheel, which requires an axle and socket to actually be useful, is not as simple a device as it may seem. Making and balancing a wheel requires a skilled Wheelwright. Skill is a measure of a worker's expertise specialization wages and supervisory capacity A wheelwright (or Wainwright) is a person who builds or repairs Wheels Making and balancing a wheel is skilled work.

Early wheels were simple wooden disks with a hole for the axle. Because of the structure of wood a horizontal slice of a trunk is not suitable, as it does not have the structural strength to support weight without collapsing; rounded pieces of longitudinal boards are required. Wood is hard fibrous lignified structural tissue produced as secondary Xylem in the stems of Woody plants notably trees but also shrubs

The oldest such wheel, believed to have been made by the Alekern tribe, was found by the Slovenian archaeologist Janez Dirjec in 2002 CE(common era) at the Ljubljana Marshes (Ljubljansko barje), some 20 kilometres southeast of Ljubljana, Slovenia. Ljubljana ( is the largest and Capital city of Slovenia. It is located in the center of the country and is a mid-sized city of some 270000 inhabitants Slovenia, officially the Republic of Slovenia (Republika Slovenija) is a Country in southern Central Europe bordering Italy to the west ^[6] According to the experts in Vienna, Austria, the specimen was manufactured somewhere between 3350 and 3100 BC, and is even older than others of similar construction found in Switzerland and Germany. Vienna ( in Wien; see also other names) is the Capital of Austria, and is also one of the nine States of Austria. Austria (Österreich ( officially the Republic of Austria (Republik Österreich Switzerland (English pronunciation; Schweiz Swiss German: Schwyz or Schwiiz Suisse Svizzera Svizra officially the Swiss Confederation Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe.

The spoked wheel was invented more recently, and allowed the construction of lighter and swifter vehicles. A spoke is one of some number of rods radiating from the center of a Wheel (the hub where the Axle connects connecting the hub with the round traction surface The earliest known examples are in the context of the Andronovo culture, dating to ca 2000 BC. Indo-Iranian originspng|thumb|300px|Archaeological cultures associated with Indo-Iranian migrations (after EIEC) Shortly later, horse cultures of the Caucasus region used horse-drawn spoked-wheel war chariots for the greater part of three centuries. The Caucasus ( also referred to as North Caucasus) is a geopolitical region located between Europe Asia & Middle East The chariot is the earliest and simplest type of Carriage, used in both peace and war as the chief vehicle of many ancient peoples They moved deep into the Greek peninsula where they joined with the existing Mediterranean peoples to give rise, eventually, to classical Greece after the breaking of Minoan dominance and consolidations led by pre-classical Sparta and Athens. The Minoan civilization was a Bronze Age civilization which arose on the island of Crete. The city of Sparta ( Doric Σπάρτα Attic Σπάρτη Athens (ˈæθənz Αθήνα Athina,) the Capital and largest city of Greece, dominates the Attica periphery as one of the world's Celtic chariots introduced an iron rim around the wheel in the 1st millennium BC. Celts (ˈkɛlts or /ˈsɛlts/, see Names of the Celts Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 The spoked wheel had been in continued use without major modification until the 1870s CE, when wire wheels and pneumatic tires were invented. Events and Trends Technology The invention of the prototype telephone by Alexander G This article is about tires used on road Vehicles including pneumatic tires and solid tires. ^[7]

The invention of the wheel has also been important for technology in general, important applications including the water wheel, the cogwheel (see also antikythera mechanism), the spinning wheel, and the astrolabe or torquetum. Technology is a broad concept that deals with a Species ' usage and knowledge of Tools and Crafts and how it affects a species' ability to control and adapt A water wheel is a means of extracting power from the flow (or fall of water otherwise known as Hydropower. This is the page for mechanical Gears For other uses see Gear (disambiguation For the gear-like device used to drive a roller chain see Sprocket The Antikythera mechanism (ˌæntɪkɪˈθɪərə an-ti-ki- theer -uh is an ancient mechanical Calculator (also described as the first known " mechanical A spinning wheel is a device for spinning thread or Yarn from natural or Synthetic Fibers History Technology in World Civilization The astrolabe is a historical Astronomical instrument used by classical astronomers, Navigators The torquetum or turquet is a medieval astronomical instrument designed to take and convert measurements made in three sets of coordinates Horizon equatorial and More modern descendants of the wheel include the propeller, the jet engine, the flywheel (gyroscope) and the turbine. A propeller is essentially a type of fan which transmits power by converting Rotational motion into Thrust for propulsion of a vehicle such as an specific --->A jet engine is a Reaction engine that discharges a fast moving jet of Fluid to A flywheel is a mechanical device with significant Moment of inertia used as a storage device for Rotational energy. A gyroscope is a device for measuring or maintaining orientation, based on the principles of Angular momentum. A turbine is a rotary Engine that extracts Energy from a Fluid flow

Mechanics and function

The wheel is a device that enables efficient movement of an object across a surface where there is a force pressing the object to the surface. Common examples are a cart drawn by a horse, and the rollers on an aircraft flap mechanism.

The wheel is not a machine, and should not be confused with the wheel and axle, one of the simple machines. The wheel and axle is a Simple machine. The traditional form as recognised in 19th century textbooks is as shown in the image In Physics, especially Mechanics, a simple machine is a mechanical device that changes the direction or magnitude of a Force. A driven wheel is a special case, that is a wheel and axle. The wheel and axle is a Simple machine. The traditional form as recognised in 19th century textbooks is as shown in the image Note that wheels predate driven wheels by about 6000 years.

Wheels are used in conjunction with axles, either the wheel turns on the axle, or the axle turns in the object body. An axle is a central shaft for a rotating Wheel or Gear. In some cases the axle may be fixed in position with a bearing or Bushing The mechanics are the same in either case.

The low resistance to motion (compared to dragging) is explained as follows (refer to friction):

• the normal force at the sliding interface is the same. Friction is the Force resisting the relative motion of two Surfaces in contact or a surface in contact with a fluid (e
• the sliding distance is reduced for a given distance of travel.
• the coefficient of friction at the interface is usually lower.

Bearings are used to reduce friction at the interface. A bearing is a device to permit constrained relative motion between two parts typically rotation or linear movement

Example:

• If dragging a 100 kg object for 10 m along a surface with μ = 0. The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International 5, the normal force is 981 N and the work done (required energy) is (work=force x distance) 981 × 0. In Physics, the normal force F_n\ (or in some books N) is the component perpendicular to the surface of contact of the Contact force The newton (symbol N) is the SI derived unit of Force, named after Isaac Newton in recognition of his work on Classical In Physics, mechanical work is the amount of Energy transferred by a Force. In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός 5 × 10 = 4905 joules. The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity
• Now give the object 4 wheels. The normal force between the 4 wheels and axles is the same (in total) 981 N, assume μ = 0. 1, and say the wheel diameter is 1000 mm and axle diameter is 50 mm. Geometry, a diameter of a Circle is any straight Line segment that passes through the center of the circle and whose Endpoints are on the So while the object still moves 10 m the sliding frictional surfaces only slide over each other a distance of 0. 5 m. The work done is 981 x 0. 1 x 0. 5 = 49 joules.

Additional energy is lost at the wheel to road interface. This is termed rolling resistance which is predominantly a deformation loss. Rolling resistance, sometimes called rolling friction or rolling drag, is the resistance that occurs when a round object such as a ball or Tire

Alternatives to wheels

While wheels are used for ground transport very widely, there are alternatives, some of which are suitable for terrain where wheels are ineffective. Alternative methods for ground transport without wheels (wheel-less transport) include:

• Being raised by electromagnetic energy (maglev train and other vehicles)
• Dragging with runners (sled) or without (travois)
• Being raised by air pressure (hovercraft)
• Riding an animal such as a horse
• Human powered:
  • Walking on one's own legs
  • Being carried (litter/sedan chair or stretcher)
• A walking machine
• Caterpillar tracks (although it is still operated by wheels)
• Spheres, as used by the Audi RSQ concept car, and Dyson vacuum cleaners

Wheels as symbols

The Romani flag

In the Unicode computer standard, the Dharmacakra is called the "Wheel of Dharma" and found in the eight-spoked form. Electromagnetism is the Physics of the Electromagnetic field: a field which exerts a Force on particles that possess the property of MAGLEV, or magnetic levitation, is a system of transportation that suspends guides and (usually propels vehicles predominantly trains using magnetic forces A sled, sledge or sleigh is a Vehicle with runners for sliding instead of wheels for rolling A travois ( Canadian French, from French travail, a frame for restraining horses also obsolete travoy or travoise) is a frame A hovercraft, or air-cushion vehicle (ACV is an Amphibious vehicle or craft, designed to travel over any sufficiently smooth surface supported by For the Roman class see Equestrian (Roman Equestrianism refers to the skill of riding or driving Horses This broad description A working animal is an animal that is kept by humans and trained to perform tasks The horse ( Equus caballus) is a hoofed ( Ungulate) Mammal, one of eight living species of the family Equidae. Walking (also called ambulation) is the main form of Animal Locomotion on land, distinguished from Running and crawling A leg is a limb on an Animal 's Body that supports the rest of the animal above the ground between the Ankle and the Hip and is used for The litter is a class of Wheelless Vehicles a type of Human-powered transport, for the transport of persons A stretcher is a Medical device used to carry casualties or an incapacitated person from one place to another A walker is a vehicle that moves on legs rather than wheels or tracks. Continuous tracks are large (modular tracks used on the so-called caterpillar Tanks construction equipment and certain other off-road vehicles "Globose" redirects here See also Globose nucleus. A sphere (from Greek σφαίρα - sphaira, "globe The Audi RSQ is a Mid-engined Concept car developed by Audi AG for use as a Product placement in the 2004 Sci-fi movie Dyson is a British appliances manufacturer Its main products are Vacuum cleaners that use Cyclonic separation. In Computing, Unicode is an Industry standard allowing Computers to consistently represent and manipulate text expressed in most of the world's The Dharmachakra ( Sanskrit) or Dhammachakka ( Pāli) Tibetan chos kyi 'khor lo, Chinese fălún 法輪 The Sanskrit term ( Devanāgarī: धर्म Pali transliteration dhamma) is an Indian spiritual and religious It is represented as U+2638 (☸)

The wheel has also become a strong cultural and spiritual metaphor for a cycle or regular repetition (see chakra, reincarnation, Yin and Yang among others). Culture (from the Latin cultura stemming from colere, meaning "to cultivate" generally refers to patterns of human activity and the symbolic Chakra ( Pali: chakka Tibetan: khorlo Malay: cakera is a Sanskrit term meaning Circle or Wheel In Chinese philosophy, the concept of yin and yang ( is used to describe how seemingly opposing forces are bound together intertwined and interdependent in the As such and because of the difficult terrain, wheeled vehicles were forbidden in old Tibet. Tibetan history is characterized by a special dedication to the Buddhist religion both in the eyes of its own people as well as for the Mongol and Manchu

The winged wheel is a symbol of progress, seen in many contexts including the coat of arms of Panama and the logo of the Ohio State Highway Patrol. The Panamanian Coat of Arms is a Heraldic symbol for the Central American Nation of Panama. The Ohio State Highway Patrol is a division of the Ohio Department of Public Safety and is the official Highway patrol and de facto State police

The introduction of spoked (chariot) wheels in the Middle Bronze Age appear to have carried somewhat of a prestige. The chariot is the earliest and simplest type of Carriage, used in both peace and war as the chief vehicle of many ancient peoples The solar wheel appears to have a significance in Bronze Age religion, replacing the earlier concept of a Solar barge with the more "modern" and technologically advanced solar chariot. The sun cross, a Cross inside a Circle, is one of the oldest and most widespread of symbols Prehistoric religion is a general term for the religious beliefs and practices of prehistoric peoples "Sun god" redirects here For the Ramsey Lewis album see Sun Goddess (album. "Sun god" redirects here For the Ramsey Lewis album see Sun Goddess (album.

The wheel is also the prominent figure on the flag of India. "Indian flag" redirects here For flags used by Native American peoples see the tribes' respective articles, for example the Navajo Nation. The wheel in this case represents law (dharma). The Sanskrit term ( Devanāgarī: धर्म Pali transliteration dhamma) is an Indian spiritual and religious It also appears in the flag of the Romani people, hinting to their nomadic history and their Indian origins. The Romani flag ( O styago le romengo in Romani) is the international flag of the Romani people.

In recent times, the custom aftermarket car/automobile roadwheel has become a status symbol. The automotive aftermarket is the part of the automotive industry concerned with the Manufacturing, Remanufacturing, Distribution, Retailing, A status symbol is a visible external denotation of one's social position and indicator of status. These wheels are often incorrectly referred to as "rims". Bicycle Wheel is a readymade by Marcel Duchamp consisting of a bicycle fork with front wheel mounted upside-down on a wooden stool The term "rim" is incorrect because the rim is only the outer portion of a wheel (where the tire is mounted), just as with a coffee cup or meteor crater. These "rims" have a great deal of variation, and are often highly polished and very shiny. Some custom "rims" include a bearing-mounted, free-spinning disc which continues to rotate by inertia after the automobile is stopped. The vis insita or innate force of matter is a power of resisting by which every body as much as in it lies endeavors to preserve in its present state whether it be of rest or of moving In slang, these are referred to as "Spinners". A spinner is a type of Hubcap that spins independently inside of a Wheel itself when the vehicle is in motion and continues to spin once the vehicle has come to a

See also

• Alloy wheel
• Artillery wheel
• Axle
• Bicycle wheel
• Big wheel
• Breaking wheel, a form of torture
• Caster
• Color wheel
• Pressed Steel wheel
• Driving wheel
• Ferris wheel
• Hubcap
• Magnetic levitation and wheel-less
• Mecanum wheel
• Reinventing the wheel
• Rim
• Rolling friction
• Ship's wheel
• Simple machine
• Square wheel
• Steering wheel
• Tire
• Tweel
• Wagon-wheel effect
• Wheel and axle
• Wheel sizing
• Wire wheels
• Wheel of Fortune
• Wheelset (railroad)
• Terrestrial locomotion in animals: Rolling

Gallery of images

A driving wheel on a steam locomotive	0 Series Shinkansen wheel	Modern motorcycle alloy wheel with disc brake	A pair of wheels on a cart
Training wheels are used to help the learner cope with gravity

References