Clock

For other uses, see Clock (disambiguation). A wall clock

A clock (from the Latin cloca, "bell") is an instrument for measuring time. (Usually, for measuring time of intervals less than a day--as opposed to a calendar.) Those used for technical purposes, of very high accuracy, are sometimes called chronometers. A portable clock is called a watch. The clock in its most common modern form (in use since at least the 14th century) displays the hours, minutes, and sometimes seconds that pass over a twelve or twenty-four-hour period.

History

A replica of an ancient Chinese incense clock

The clock is one of the oldest human inventions. In principle, it requires no more than some physical process which will proceed at a known rate, and a way to gauge how long that process has been continuing. As the seasons and the phases of the moon can be used to measure the passage of longer periods of time, shorter processes could be used to measure off hours and minutes. The sundial, which measures the time of day by the direction of shadows cast by the sun, was widely known in ancient times. Candles and sticks of incense which burn down at approximately predictable speeds have also been used as clocks. In an hourglass fine sand pours through a tiny hole at a predictable rate.

The historian Vitruvius reported that the ancient Egyptians also used a clepsydras, a time mechanism run by flowing water. Historians disagree over the Antikythera mechanism but this is largely thought to be an early mechanical clock. By the 9th century AD a mechanical timekeeper had been developed that lacked only an escapement mechanism. There is a record that in 1176 Sens Cathedral installed a ‘horologe’—the word still used in French for large clocks. (from Greek hora, hour, and legein, to tell). This word has led scholars to believe that these tower clocks did not employ hands or dials, but “told” the time with audible signals such as bells.

A variety of mechanical clocks were produced by Spanish Muslim engineers, both large and small, and this knowledge was transmitted to Europe through Latin translations of Islamic books on mechanics. These clocks were weight-driven. Designs and illustrations of epi-cyclic and segmental gears were provided. One such clock included a mercury escapement. The latter type was directly copied by Europeans during the 15th century. In addition, during the 9th century, Ibn Firnas of Islamic Spain, according to Will Durant, invented a watch-like device which kept accurate time. The Muslims also constructed a variety of highly accurate astronomical clocks for use in their observatories.

The earliest reasonably accurate clocks are the 13th century tower clocks probably developed for (and perhaps by) monks in Northern Italy. These were used to announce the canonical hours or intervals between set times of prayer. Canonical hours differ in length, and varied as the times of sunrise and sunset shifted.

The earliest table clocks that survive in any quantity are mid-16th century ones from the metalworking towns of Nuremberg and Augsburg. These clocks have only one hand. The dial between the hour markers is divided into four equal parts making the clocks readable to the nearest 15 minutes.

The massive clock on Big Ben, London, England. The 5 foot 4 inch (1.63 m) person "holding on" to the six o'clock marking has been inserted into the picture at correct scale. The hour hand is 9 feet (2.7 m) long and the minute hand is 14 feet (4.3 m) long

The next major development in accuracy occurred in 1657 with the invention of the pendulum clock. Galileo had the idea to use a swinging bob to propel the motion of a time telling device earlier in the 17th century. Christiaan Huygens, however, is usually credited as the inventor. He determined the mathematical formula that related pendulum length to time (99.38 cm or 39.13 inches for the one second movement) and had the first pendulum driven clock made. In 1670, the English clockmaker William Clement created the anchor escapement, an improvement over Huygens' crown escapement. Within just one generation, minute hands and then second hands were added.

The excitement over the pendulum clock attracted the attention of designers resulting in a proliferation of clock forms. Notably, the longcase clock (aka grandfather clock) was created to house the pendulum and works. The English clockmaker William Clement, inventor of the anchor escapement, is credited with developing this form in 1670. It was also at this time that clock cases began to be made of wood and clock faces to employ enamel. On November 17, 1797, Eli Terry received his first patent for a clock. Terry is known as the founder of the American clock-making industry.

The development of electronics in the twentieth century led to clocks with no clockwork parts at all. Time in these cases is measured in several ways, such as by the behaviour of quartz crystals, or the decay of radioactive elements. Even mechanical clocks have since come to be largely powered by batteries, removing the need for winding.

Types

There are two major types of clocks.

Analog clocks

Analog clocks may be mechanical or have a quartz movement. A clock face is the part of an analog clock that tells time through the use of a fixed numbered dial or dials and moving hand or hands. It usually has a circular scale of 12 hours, which also serves as a scale of 60 minutes, and often also as a scale of 60 seconds. The analog clock with digital display emulates a digital clock but with an analog movement. The ultimate analog clock is the sundial, which tracks the sun continuously, registering the time by the shadow of its gnomon.

Basic digital clock radio.

Digital clocks

Digital clocks use electronic methods of keeping time, typically the 50 or 60 hertz oscillation of AC power or a crystal oscillator as in a quartz movement. A digital clock typically displays a numerical hour range of 0-23, or 1-12 (with an indication of AM or PM) using an LCD or LED display, although digital versions of analog-style faces exist. Mains-driven digital clocks are often reset after a power failure, and, typically, begin flashing to alert us that the time they display is incorrect. After a reset digital clocks lacking a backup battery either start counting from 00:00, or stay 00:00 to indicate that their time needs to be set.


Purposes

Clocks are in homes and offices; smaller ones (watches) are carried; larger ones are in public places, e.g. a train station or church. A small clock is often shown in a corner of computer displays or mobile phones.

The main purpose of a clock is not always to display the time. It may also be used to control a device according to time, e.g. an alarm clock, a VCR, or a time bomb (see: counter).

Practically all computers depend on an accurate internal clock signal to allow synchronized processing. (A few research projects are developing CPUs based on asynchronous circuits). Some computers also maintain time and date for all manner of operations whether these be for alarms, event initiation or just to display the time of day.

Ideal clocks

An ideal clock is a scientific principle that measures the ratio of the duration of natural processes, and thus will give the time measure for use in physical theories. Therefore, to define an ideal clock in terms of any physical theory would be circular. An ideal clock is more appropriately defined in relationship to the set of all physical processes.

A desk clock

This leads to the following definitions:

  • A clock is a recurrent periodic process and a counter.
  • A good clock is one which, when used to measure other recurrent processes, finds many of them to be periodic.
  • An ideal clock is a clock (i.e., recurrent process) that makes the most other recurrent processes periodic.

The recurrent, periodic process (a metronome) is an oscillator and typically generates a clock signal. Sometimes that signal alone is (confusingly) called "the clock," but sometimes "the clock" includes the counter, its indicator, and everything else supporting it.

This definition can be further improved by the consideration of successive levels of smaller and smaller error tolerances. While not all physical processes can be surveyed, the definition should be based on the set of physical processes which includes all individual physical processes which are proposed for consideration. Since atoms are so numerous and since, within current measurement tolerances, they all beat in a manner such that if one is chosen as periodic then the others are all deemed to be periodic also, it follows that atomic clocks represent ideal clocks to within present measurement tolerances and in relation to all presently known physical processes. However, they are not so designated by fiat. Rather, they are designated as the current ideal clock because they are currently the best instantiation of the definition.

Navigation

Accurate navigation by ships beyond the sight of land depends on the ability to measure latitude and longitude. Latitude is fairly easy to determine through celestial navigation, but the measurement of longitude requires accurate measurement of time. This need was a major motivation for the development of accurate mechanical clocks. John Harrison created the first, highly accurate marine chronometers in the mid-18th century. The Noon gun in Cape Town still fires an accurate signal to allow ships to check their chronometers.

Modern clocks

Quartz timepieces were invented in the 1920s.

The digital clock was invented in 1956.

Specific types of clocks

A windup, mechanical, spring-driven alarm clock.
  • alarm clock
  • analog clock with digital display
  • astronomical clock
  • atomic clock
  • binary clock
  • bracket clock
  • cartel clock
  • chiming clock
  • clock network
  • Data clock for timescapes created with time-technology
  • doll's head clock
  • Railroad chronometers
  • countdown clock
  • cuckoo clock
  • flip clock
  • game clock
  • grandfather clock
  • hourglass
  • longcase clock
  • mantel clock
  • pedestal clock
  • swinging pendulum clock
  • torsion pendulum clock
  • projection clock
Digital clock display in an oven.
  • quartz clock
  • sidereal clock
  • skeleton clock
  • stopwatch
  • striking clock
  • sundial
  • tide clock
  • time clock
  • watch
  • water clock
  • world clock

This page about Clocks includes information from a Wikipedia article.
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The digital clock was invented in 1956. Although a few Corvairs have been modified to accept the Chevrolet big-block engine, the added size of the engine makes the work significantly more difficult, and the result, although a great performer, tends to be unreliable. Quartz timepieces were invented in the 1920s. An advantage of this modification is that the rearward weight distribution gives excellent traction without the need for slick or "cheater slick" tires, let alone modifying the wheelbase as on the FX cars of the time The mid-engine design also provides optimal handling characteristics. The Noon gun in Cape Town still fires an accurate signal to allow ships to check their chronometers. Crown's prototype with 350 horsepower (261 kW) Corvette engine recorded an elapsed time of 12.22 seconds and 105 miles per hour (169 km/h) in the quarter mile (402 m). John Harrison created the first, highly accurate marine chronometers in the mid-18th century. The resulting vehicle weighed only 2,750 pounds (1250 kg), compared to 3,700 pounds (1680 kg) for a small block Corvette, and possessed independent rear suspension of almost the same design.

This need was a major motivation for the development of accurate mechanical clocks. A complete kit to adapt a Chevrolet small-block V8 to a Corvair was manufactured by a company named Crown Manufacturing, for $600. Latitude is fairly easy to determine through celestial navigation, but the measurement of longitude requires accurate measurement of time. However, the former engine compartment in the rear now is available as luggage space. Accurate navigation by ships beyond the sight of land depends on the ability to measure latitude and longitude. A radiator occupies the former trunk, in the front of the vehicle. Rather, they are designated as the current ideal clock because they are currently the best instantiation of the definition. As daunting as this might seem, two things made it possible:.

However, they are not so designated by fiat. The ultimate Corvair modification was replacement of the engine with a V8. Since atoms are so numerous and since, within current measurement tolerances, they all beat in a manner such that if one is chosen as periodic then the others are all deemed to be periodic also, it follows that atomic clocks represent ideal clocks to within present measurement tolerances and in relation to all presently known physical processes. He still retains the prototype however, and occasionally exhibits it at car shows. While not all physical processes can be surveyed, the definition should be based on the set of physical processes which includes all individual physical processes which are proposed for consideration. Unfortunately, the Traffic Safety Act of 1966 placed restrictions on the ability to produce automobiles on a small scale; this was followed by Chevrolet's decision to terminate production of the Corvair, which confirmed the end of Fitch's plan. This definition can be further improved by the consideration of successive levels of smaller and smaller error tolerances. With a total weight of 1,950 pounds (885 kg), even with a steel body, and with the Corvair engine modified with Weber carburetors to deliver 175 horsepower (130 kW), the car delivered spirited performance for $8,760.

Sometimes that signal alone is (confusingly) called "the clock," but sometimes "the clock" includes the counter, its indicator, and everything else supporting it. Fitch went on to design and build a prototype of the Fitch Phoenix, a Corvair-based two-seat sports car, superficially resembling a smaller version of the Mako Shark based Corvette. The recurrent, periodic process (a metronome) is an oscillator and typically generates a clock signal. Body options such as spoilers were available, but the most visually remarkable option was the "Ventop", a fiberglass overlay for the C-pillars and rear of the roof that gave the car a "flying buttress" profile. This leads to the following definitions:. The basic Sprint received only minor modifications to the engine, bringing it to 155 horsepower (116 kW), but upgrades to the shock absorbers and springs, adjustments to the wheel alignment, quicker steering ratio, alloy wheels, metallic brake linings, the obligatory wood-rimmed steering wheel (leather available for an additional $9.95) and other such minor alterations made it extremely competitive with European sports cars costing much more. An ideal clock is more appropriately defined in relationship to the set of all physical processes. Longtime roadracer John Fitch was particularly interested in the Corvair as the basis for a spirited road and track oriented car, due to its handling.

Therefore, to define an ideal clock in terms of any physical theory would be circular. Comedian, television star, and car enthusiast Tim Allen currently owns and races Yenko Stinger #YS-043. An ideal clock is a scientific principle that measures the ratio of the duration of natural processes, and thus will give the time measure for use in physical theories. A total of 185 Stingers are believed to have been built, the last being YS-9700 built for Goodyear Tire and Rubber Company as a tire test vehicle in 1969 – 1970. Some computers also maintain time and date for all manner of operations whether these be for alarms, event initiation or just to display the time of day. It is believed that only fourteen 1967 Stingers were built, but Dana Chevrolet, who distributed Stingers on the US West Coast, ordered an additional three similar cars to be built to Stinger specifications, but with the AIR injection system to meet California emissions laws, with Yenko's permission. (A few research projects are developing CPUs based on asynchronous circuits). The SCCA, on the other hand, had relaxed its ruling regarding color, and the cars were available in red or blue.

Practically all computers depend on an accurate internal clock signal to allow synchronized processing. The Monza instrumentation, however, did not have a tachometer or head temperature gauges, which had to be separately installed. an alarm clock, a VCR, or a time bomb (see: counter). The next year, however, Chevrolet dropped the Corsa line, and the Monza line was not initially available stock with the four carburetor engine; the engine was eventually offered as a special performance option, however, along with the 3.89 differential. It may also be used to control a device according to time, e.g. By the end of the 1966 season, Jerry Thompson had won the Central Division Championship and placed fifth in the 1966 Nationals, Dick Thompson, a highly successful Corvette race driver, had won the Northeast Division Championship, and Jim Spencer had won the Central Division Championship, with Dino Milani taking second place. The main purpose of a clock is not always to display the time. The Stingers competed in Class D Production, which was dominated by the Triumph TR4, which was very quick in racing trim; however in its first race in January 1966, the Stinger was able to come in second by only one second.

A small clock is often shown in a corner of computer displays or mobile phones. All were equipped by the Chevrolet factory with heavy duty suspension, four speed transmission, quicker steering ratio, positraction differentials (50 with 3.89 gears, and 50 with 3.55 when Chevrolet dropped the 3.89) and dual brake master cylinders (the first application of this by Chevrolet, to become stock equipment the next year). a train station or church. Although all were white, as the SCCA required for American cars at the time, there was a great deal of variety between individual cars; some had exterior modifications including fiberglass engine covers with spoilers, some did not; some received engine upgrades developing 160, 190, 220, or 240 hp (119, 142, 164, or 179 kW). Clocks are in homes and offices; smaller ones (watches) are carried; larger ones are in public places, e.g. As the SCCA required 100 cars to be manufactured to homologate the model for production racing, Yenko completed 100 Stingers in one month in 1965.
. As the stock Corvair did not fit into any of the SCCA categories, Yenko had to modify four-carburetor Corsas into "sports cars" by removing the back seat; in the process he would introduce various performance improvements.

After a reset digital clocks lacking a backup battery either start counting from 00:00, or stay 00:00 to indicate that their time needs to be set. Don Yenko, who had been racing Corvettes, could not compete successfully against the Carroll Shelby Mustangs after they arrived on the scene; he therefore decided to race modified Corvairs, beginning with the 1966 model. Mains-driven digital clocks are often reset after a power failure, and, typically, begin flashing to alert us that the time they display is incorrect. From the first appearance of the Corvair, a large selection of high-performance equipment and modifications became available for it. A digital clock typically displays a numerical hour range of 0-23, or 1-12 (with an indication of AM or PM) using an LCD or LED display, although digital versions of analog-style faces exist. Many sports car purists were more interested in the Corvair (particularly the 1965 and later cars) than in more conventional designs, such as the Ford Mustang, despite the latter's power advantage. Digital clocks use electronic methods of keeping time, typically the 50 or 60 hertz oscillation of AC power or a crystal oscillator as in a quartz movement. These changes were, however, viewed as Chevrolet's recognition of possible problems with the original design.

The ultimate analog clock is the sundial, which tracks the sun continuously, registering the time by the shadow of its gnomon. In 1965 the Corvair got a state of the art fully independent rear suspension closely resembling that of the contemporary Corvette, even sharing some components. The analog clock with digital display emulates a digital clock but with an analog movement. Although Nader probably overstated the severity of the handling problems, as was later found by US National Highway Traffic Safety Administration investigators, Chevrolet made changes to the suspension: in 1964, adding a transverse leaf spring extending between the rear wheels to limit rear wheel camber change. It usually has a circular scale of 12 hours, which also serves as a scale of 60 minutes, and often also as a scale of 60 seconds. See Firestone vs Ford Motor Company controversy. A clock face is the part of an analog clock that tells time through the use of a fixed numbered dial or dials and moving hand or hands. The Ford Explorer had widely-publicized stability problems when equal pressures were used.

Analog clocks may be mechanical or have a quartz movement. It should be mentioned that the Corvair is by no means unique in requiring dissimilar front and rear tire pressures for normal controllability. There are two major types of clocks. Although this pressure was quite adequate for the very lightweight Corvair front end, owners and mechanics, either through ignorance of the necessity for this pressure differential between front and rear or thinking that the pressure was too low for the front, would frequently inflate the front tires to more "normal" pressures, thus ensuring that the rear of the car would lose traction before the front, causing it to oversteer. Even mechanical clocks have since come to be largely powered by batteries, removing the need for winding. In addition, the car was designed to avoid terminal oversteer by using very low air pressure in the front tires, typically 12 to 15 pounds force per square inch (80 to 100 kPa), so that they would begin to understeer (slip) before the swing axle oversteer would come into play. Time in these cases is measured in several ways, such as by the behaviour of quartz crystals, or the decay of radioactive elements. Both of these factors would have greatly increased the potential for excessive body lean and over-cambering of the suspension in sharp turns, as compared with smaller and lighter contemporary Volkswagens, Renaults, Porsches, and other rear-engined cars.

The development of electronics in the twentieth century led to clocks with no clockwork parts at all. In defense of Nader's criticism of the Corvair's swing axle rear suspension, some writers have pointed to a critical factor in the combination of soft "American-style" springs together with an unusually large and heavy engine for a rear-engine, air-cooled car. Terry is known as the founder of the American clock-making industry. Chevrolet, aware of Nader's criticism, changed the steering shaft to a two-part design with a frangible joint in the 1966 model year, and a collapsible steering column was provided in 1967, towards the end of the model's life span. On November 17, 1797, Eli Terry received his first patent for a clock. Any increase in risk of injury due to steering column intrusion in a front-end collision was, however, more than offset by the absence of an incompressible engine and transmission in the front of the vehicle, which commonly intruded into passenger compartments on vehicles of the era. It was also at this time that clock cases began to be made of wood and clock faces to employ enamel. In practice, most driver chest injuries were sustained due to the lack of a shoulder belt, rather than steering column intrusion.

The English clockmaker William Clement, inventor of the anchor escapement, is credited with developing this form in 1670. While the Corvair's steering box was mounted ahead of the front cross-member, it was well behind the frame horns, in what would later be called a "crumple zone," and could, in a severe front-end collision, push the steering column and steering wheel toward the driver. Notably, the longcase clock (aka grandfather clock) was created to house the pendulum and works. Like most cars of its era, the Corvair's steering column was rigid and could impale the driver in a front-end collision. The excitement over the pendulum clock attracted the attention of designers resulting in a proliferation of clock forms. A criticism in Lawyer Ralph Nader's 1965 book concerned the steering column design. Within just one generation, minute hands and then second hands were added. This air contamination problem is illustrated by the fact that many American cities' taxi regulations had prohibited air-cooled engine cars from being used as taxicabs when they derived their heated air from engine exhaust heat, decades before the Corvair and VW Beetle entered the market.

In 1670, the English clockmaker William Clement created the anchor escapement, an improvement over Huygens' crown escapement. The VW Beetle, likewise, was susceptible to poor engine perimeter seal maintenance resulting in contaminated air being sucked into the cooling fan, which supplied passenger compartment heat as in the Corvair. He determined the mathematical formula that related pendulum length to time (99.38 cm or 39.13 inches for the one second movement) and had the first pendulum driven clock made. The Beetle heater system better isolated fresh air from engine cooling air fumes, and was only susceptible to carbon monoxide contamination from the two heat exchanger to muffler seals at the rear of the engine, as opposed to the eight exhaust joints in the Corvair system. Christiaan Huygens, however, is usually credited as the inventor. This may have been a source of noxious interior fumes in that vehicle as well, and was also a fire hazard if the battery terminal insulator was not placed over the battery and someone or something heavy sat on the seat. Galileo had the idea to use a swinging bob to propel the motion of a time telling device earlier in the 17th century. The Volkswagen Beetle (Type I), another automobile with an air cooled engine, located the battery in the passenger compartment under the rear seat.

The next major development in accuracy occurred in 1657 with the invention of the pendulum clock. Chevrolet installed special battery caps and hoses that vented the battery to air outside the engine compartment, but these were often discarded by owners during the car's life. The dial between the hour markers is divided into four equal parts making the clocks readable to the nearest 15 minutes. The battery, which was mounted in the engine compartment, could emit sulfuric acid vapor if overcharged. These clocks have only one hand. The interior air would also be contaminated if the voltage regulator allowed an over-voltage condition and the original battery vent hoses were not attached. The earliest table clocks that survive in any quantity are mid-16th century ones from the metalworking towns of Nuremberg and Augsburg. Chevrolet wrestled with several problems of this nature the entire time the Corvair was in production with varying degrees of success.

Canonical hours differ in length, and varied as the times of sunrise and sunset shifted. Another common problem in the earlier years was oil leakage caused by dissimilar metal thermal expansion on the aluminum and steel engine. These were used to announce the canonical hours or intervals between set times of prayer. That air might also become noxious if a 6-inch (152 mm) wide rubber seal almost 16 feet (5 m) long, located between the engine assembly and the body, was not maintained in like-new condition. The earliest reasonably accurate clocks are the 13th century tower clocks probably developed for (and perhaps by) monks in Northern Italy. Chronic oil leakage from the pushrod tubes, caused by GM's poor choice of pushrod tube seal material, also contaminated the passenger heating air. The Muslims also constructed a variety of highly accurate astronomical clocks for use in their observatories. It operated independently from fuel in the cars' gas tank, but this feature became optional in 1961 and was dropped in 1965 due to weak consumer demand.

In addition, during the 9th century, Ibn Firnas of Islamic Spain, according to Will Durant, invented a watch-like device which kept accurate time. The 1960 model Corvairs used a GM Harrison division gasoline heater located in the front trunk area, as its standard heater, similar to the Eberspächer heater offered as an auxiliary heater by Volkswagen as a dealer-installed option. The latter type was directly copied by Europeans during the 15th century. Carbon monoxide and other noxious or deadly gases could enter the sedan passenger areas if exhaust system gaskets aged or failed using this system, since the gaskets were inside the heater box air intakes and air for engine cooling and passenger heating was mixed together as one common airflow. One such clock included a mercury escapement. An engineering weakness not generally highlighted related to fumes and gases entering the passenger area via the heater system, a problem endemic to an air-cooled engine that uses heat radiated from the engine directly to heat air for the passenger compartment. Designs and illustrations of epi-cyclic and segmental gears were provided. The Chevrolet Corvair engine, unique for an American car, presented a different set of requirements for mechanics, many of whom treated the engine in the same way as they would an engine of normal design, leading to problems.

These clocks were weight-driven. It is not known how many were completed. A variety of mechanical clocks were produced by Spanish Muslim engineers, both large and small, and this knowledge was transmitted to Europe through Latin translations of Islamic books on mechanics. The finished car was not sold as a restoration, but with newer headlights and taillights and minor mechanical improvements, as a sort of an update. This word has led scholars to believe that these tower clocks did not employ hands or dials, but “told” the time with audible signals such as bells. In the 1970s an abortive attempt was made by Corvair tuner John Fitch (driver) to found a company dedicated to acquiring 1965 – 1969 Corvairs in good condition and rebuilding them from the ground up. (from Greek hora, hour, and legein, to tell). Although negative publicity hurt the Corvair, ongoing litigation is believed to have extended the production life of the vehicle, as ending production would have been construed as an admission by General Motors that the product was flawed.

There is a record that in 1176 Sens Cathedral installed a ‘horologe’—the word still used in French for large clocks. Corvair production finally ceased in 1969 with sales of only 6,000 cars, a victim of Nader's book, Ford's Mustang, and Chevrolet's own Camaro and Nova. By the 9th century AD a mechanical timekeeper had been developed that lacked only an escapement mechanism. This model year was the first equipped with true collapsible steering columns, a final response to one of the most valid safety criticisms. Historians disagree over the Antikythera mechanism but this is largely thought to be an early mechanical clock. In 1968 the line was trimmed even further to just the coupe and convertible, and sales were down to 15,400. The historian Vitruvius reported that the ancient Egyptians also used a clepsydras, a time mechanism run by flowing water. The 140 hp (104 kW) and 180 hp (134 kW) engine options were deleted as well, although the 140 HP option would be later reintroduced as a Regular Production Option and would remain available until Corvair production ended.

In an hourglass fine sand pours through a tiny hole at a predictable rate. In 1967 the Camaro was introduced and the Corvair line was trimmed to the base 500 sedan and coupe, and the Monza sedan, coupe and convertible. Candles and sticks of incense which burn down at approximately predictable speeds have also been used as clocks. It is a popular retrofit to the 1965 models both for functional and aesthetic reasons. The sundial, which measures the time of day by the direction of shadows cast by the sun, was widely known in ancient times. A small flexible plastic air dam was installed below the front apron to alleviate problems with front-end lift at high speeds. As the seasons and the phases of the moon can be used to measure the passage of longer periods of time, shorter processes could be used to measure off hours and minutes. Also, the gear ratios were carried over from other GM cars, and were not optimal for a street-driven Corvair.

In principle, it requires no more than some physical process which will proceed at a known rate, and a way to gauge how long that process has been continuing. The new transmission was capable of handling more stress, though generally wasn't as smooth shifting as the earlier transmission. The clock is one of the oldest human inventions. One change of note was a more robust 4 speed synchromesh transmission for 1966, using the standard Saginaw gear set used by other GM vehicles. . The sales decline was also accelerated by a decision at GM to discontinue further development of the Corvair. The clock in its most common modern form (in use since at least the 14th century) displays the hours, minutes, and sometimes seconds that pass over a twelve or twenty-four-hour period. The 1966 lineup remained essentially unchanged from 1965, and sales began to decline as a result of Nader's book, the popular (and cheaper) new Mustang, and rumors of the upcoming Camaro.

A portable clock is called a watch. Chevrolet replaced the Corvair-based vans with the Chevrolet Sportvan/GMC Handi-Van, which used a traditional front engine/rear drive axle borrowed from the Chevy II. (Usually, for measuring time of intervals less than a day--as opposed to a calendar.) Those used for technical purposes, of very high accuracy, are sometimes called chronometers. 1965 would be the last year for the Greenbrier window van, which was retained only because of a few fleet orders, with less than 2000 being built. A clock (from the Latin cloca, "bell") is an instrument for measuring time. By this point, the more utilitarian station wagon, Panel Van, and pickup body styles had all been dropped in favor of the sportier coupe, hardtop sedan and convertible styles. world clock. The base 95 hp (71 kW) and 110 hp (82 kW) high performance engines were carried forward from 1964 for the 500 and Monza models.

water clock. The standard equipment Corsa 140 horsepower (104 kW) engine was notable for the fact that the engine used 4 single-throat carburetors, larger valves, and dual exhaust — the factory's response to a modification which hot-rodders had been making since the car first appeared; it was available as an option on other Corvair trim levels. watch. The Corsa came with more instruments on the panel and a short throw shifter when equipped with the manual transmission. time clock. The previous 150 hp (112 kW) Monza Spyder was replaced by the normally-aspirated 140 hp (104 kW) Corsa and the 180 hp (134 kW) Corsa Turbo. tide clock. A new fully independent suspension similar to that used on the Corvette replaced the original swing axle rear suspension.

sundial. The new body style lay somewhere between that of a baby Chevrolet Corvette Stingray and a mid-1960s Italian sports car and foreshadowed the 1967 Chevrolet Camaro that eventually replaced the Corvair. striking clock. A dramatic redesign of the Corvair body and suspension and several powerful new engines came in 1965. stopwatch. The sporty, inexpensive Ford Mustang, based on the conventionally designed Ford Falcon and introduced in late 1964 in response to the Corvair, ultimately finished off Chevrolet's bold experiment. skeleton clock. Even though a 1972 National Highway Traffic Safety Administration safety commission study ultimately exonerated the Corvair and declared it no more unsafe than any similar vehicle of its era, Nader's book, which was published in 1965, dealt a severe blow to sales of the Corvair line.

sidereal clock. However, a young lawyer named Ralph Nader had written a book called Unsafe at Any Speed in which the 1960-63 Corvair (and its purported greater tendency to roll over) was used as a dramatic case study. quartz clock. The change was insisted upon by new Chevrolet general manager Semon "Bunkie" Knudsen, who according to contemporary John DeLorean had to threaten to resign in order to get the change approved. projection clock. 1964 also saw a critical improvement in the Corvair's suspension; the car's swing axle rear suspension's tendency to lose traction suddenly and without warning when pushed to the limit was tamed by use of an additional transverse leaf spring coupling both rear wheels. torsion pendulum clock. The Rampside pickup was discontinued at the end of the model year.

swinging pendulum clock. The Spyder engine remained rated at 150 hp (112 kW)despite the displacement increase of the engine. pedestal clock. The lineup remained relatively unchanged for the 1964 model year, with the exception of the engine growing from 145 to 164 in³ (2.3 to 2.7 L)due to an increase in stroke; the base power growing from 80 to 95 hp (60 to 70 kW), and the high performance engine growing from 95 to 110 hp (70 to 80 kW). mantel clock. Significant engineering and safety changes occurred in 1964, while the bodies and models available remained the same. longcase clock. The 1963 model year saw the end of the Lakewood station wagon and Loadside pickup, and the availability of a long 3.08 gear for improved fuel economy, but the Corvair otherwise remained largely the same as in 1962.

hourglass. A convertible option was added as well. grandfather clock. The Super Deluxe Monza Spyder introduced improved brakes and suspension, and a multi-gauge instrument cluster which included a tachometer, cylinder head temperature gauge and intake manifold pressure gauge. game clock. In 1962, Chevrolet introduced the 150 hp (112 kW) turbocharged Monza Spyder, making the Corvair one of the first two production automobiles to come with a turbocharger as a factory option, (with the Oldsmobile F-85 Turbo Jetfire of the same year). flip clock. Continuing from the end of the previous year was the Monza, heavily promoted and sometimes considered "the poor man's Porsche." The Monza was expanded to a four-door as well as a two-door coupe, and garnered around 144,000 sales.

cuckoo clock. The Greenbrier Sportswagon used the same body as the Corvan with window option, but was marketed as a station wagon like the Lakewood, and was available with trim and paint options similar to the cars, arguably making it the first American Minivan. countdown clock. Rampsides were used by the Bell System because of the ease with which cable reels could be rolled in and out of the bed. Railroad chronometers. The Loadside was a fairly typical pickup of the era, except for the rear engine, forward controls, and a strange pit in the middle of the bed, The more popular pickup was the Rampside model, which, as its name implies, had a large fold-down ramp on the side of the pickup bed. doll's head clock. There were also two models of pickup available.

Data clock for timescapes created with time-technology. The Corvan model was available in a myriad of configurations as both a panel van and a window van. clock network. That same year, Chevrolet also introduced the Corvair 95 line of light-duty truck, which used the Corvair driveline and were forward-control, with the driver sitting over the front wheels, as in the Volkswagen Type 2. chiming clock. Engine heat and gasoline odors migrating up through the floor of the station wagon proved to be a persistent problem, and the wagon was relatively short-lived. cartel clock. A station wagon, the Lakewood, was also added to the lineup in 1961, and it contained a total of 68 ft³ (1.9 m³) of cargo room — 58 in the main passenger compartment, and another 10 in the "trunk" under the hood.

bracket clock. The gasoline heater remained an option through 1964. binary clock. The standard heater was changed from the gasoline heater to engine cooling air ducted into the passenger compartment. atomic clock. The high-performance engine was rated at 98 hp (73 kW). astronomical clock. The base engine was still rated at 80 hp (60 kW) when paired with the manual transmissions and 84 hp (63 kW) when mated to the optional automatic transmission.

analog clock with digital display. The Corvair engine received its first size increase to 145 in³, courtesy of a slight increase in bore size. alarm clock. For 1961 Chevrolet added an optional four-speed manual transmission to augment the standard three-speed manual and optional two-speed automatic. An ideal clock is a clock (i.e., recurrent process) that makes the most other recurrent processes periodic. Despite its late introduction, the Monza sold 12,000 copies, making it one of the most popular Corvairs. A good clock is one which, when used to measure other recurrent processes, finds many of them to be periodic. Optional was a more powerful engine rated at 95 horsepower, thanks to a more radical camshaft and low-restriction exhaust.

A clock is a recurrent periodic process and a counter. The line quickly grew from plain, four-door sedans with bench seats (the base 500 and slightly more upscale 700) to the Monza 900, a two-door coupe with bucket seats and plush trim introduced late in the model year. Passenger compartment heat was supplied by a gasoline heater mounted in the luggage compartment. A novel feature available for two-doors was a fold-down rear seat, included on some higher-level models. The early 1960 models were conceived as economy cars, and had boxy styling, basic trim, and few amenities to keep prices down despite the relatively expensive and unique powertrain.

The design was championed by Ed Cole, Chevrolet chief engineer in the early 1950s and general manager in the late 1950s, as an answer to the growing popularity of small, lightweight imported cars. The Corvair name originated as a fastback show car in 1954, which, like many Chevy concept cars of the period, were based on the Corvette, including the Chevrolet Nomad and Chevrolet Impala. . Doing so in Southern California and being caught by the Los Angeles Police Department was a guaranteed ticket to a weekend in jail.

The first Corvairs (1960 – 1964) were factory equipped with an ignition lock wherein it was possible to start the car and then remove the key. For 24 hours, the Corvair was tested at the Riverside International Raceway in Riverside, California, one car did a roll but the other did the 24 hour drive and only lost a quart (1 L) of oil (Source: Riverside Raceway Palace of Speed by Dick Wallen). The first engines produced as little as 80 hp (60 kW), but later developed as much as 180 hp (134 kW). The entire line (which eventually grew to incorporate sedans, coupes, convertibles, vans, pickups and station wagons) initially shared an aluminum, air-cooled 140 in³ (2.3 L) flat-6 engine.

The "trunk", on the other hand, was in the front of the vehicle, while the spare tire was stored above the flat engine, saving trunk space. It was a rear-engined vehicle in the style of the Volkswagen Beetle and the Porsche 356 Speedster. The Corvair was part of GM's innovative A-body line of cars, but this was by far the most unusual, due to the location and design of its engine. The Corvair — like the Ford Falcon, Studebaker Lark, Rambler, and the Plymouth Valiant — was created in response to the small, sporty and fuel-efficient automobiles being imported from Europe by Volkswagen, Renault and others.

Design began in 1956 under the auspices of Ed Cole, and the first vehicles rolled off the assembly line in late 1959 as part of the 1960 model year (in which it was named Motor Trend magazine's Car of the Year). The Corvair remains one of GMs most unusual creations. The Corvair was offered in a wide range of body styles (such as a four-door sedan, coupe, convertible, station wagon, pickup, panel van, a window van called the Greenbrier) and featured an air-cooled engine, which was unusual for American cars at the time. The Chevrolet Corvair was a rear-engined automobile produced by General Motors from 1960 to 1969.

The switch in 1966 to using standard Chevrolet Saginaw gear sets in the manual transmission could handle the torque of a V8. The Corvair engine rotated in the opposite direction from most other engines, so that if a V8 was placed in the rear seat area (the added weight of a V8 in the original location of the Corvair engine would be abominable to drive), and the transaxle was rotated 180 degrees to meet it, the gearing would drive the car in the proper direction, not four speeds in reverse and one forward.