A wall clock, with 3 dials and 5 hands

A clock face is the part of an analog clock that displays the time through the use of a fixed numbered dial or dials and moving hands. Circadian Locomotor Output Cycles Kaput, or Clock is a gene which encodes proteins regulating Circadian rhythm. In its most basic form, recognised universally throughout the world, the dial is numbered 1-12 indicating the hours in a 12-hour cycle, and a short hour hand makes 2 revolutions in a day. The hour (symbol h) is a unit of Time. It is not an SI unit but is accepted for use with the SI A longer minute hand makes one revolution every hour. A minute is a Unit of measurement of Time or of Angle. The minute is a unit of Time equal to 1/60th of an Hour or 60 The face may also include a second hand which makes one revolution per minute, and other hands. The second ( SI symbol s) sometimes abbreviated sec, is the name of a unit of Time, and is the International System of Units The term is also used for the time display on digital clocks and watches. A digital clock is a type of Clock that displays the time Digitally i

onehand-watch

A second type of clock face is the 24 hour analog dial, widely used in military and other organizations that use 24 hour time. Clocks and Watches with a 24-hour analog dial have an hour hand that makes one complete revolution 360° in a Day (24 hours per revolution A military is an Organization authorized by its Nation to use force usually including use of Weapons in defending its Country (or by attacking Description A time of day is written in the 24-hour notation in the form hhmm (for example 0123 or hhmmss (for example 012345 where hh (00 to 23 is the decimal number This is similar to the 12 hour dial above, except it has hours numbered 1-24 around the outside, and the hour hand makes only one revolution per day. Some special purpose clocks, such as timers and sporting event clocks, are designed for measuring periods less than one hour. A timer is a specialized type of Clock. A timer can be used to control the sequence of an event or process Clocks can indicate the hour with Roman numerals or Hindu-Arabic numerals. Roman numerals are a Numeral system originating in ancient Rome, adapted from Etruscan numerals. The Hindu-Arabic numeral system is a Positional Decimal Numeral system first documented in the ninth century The two numbering systems have also been used in combination with the prior indicating the hour and the later the minute. Longcase clocks (also known as grandfather clocks) typically use Roman numerals for the hours. A longcase clock, also tall-case clock, grandfather clock or floor clock, is a freestanding weight-driven Pendulum clock with the Roman numerals are a Numeral system originating in ancient Rome, adapted from Etruscan numerals. ("IIII" -rather than "IV"- is often used to mark the fourth hour to achieve symmetry with "VIII. ") Clocks using only Arabic numerals first began to appear in the mid-18th century. The periphery of a clock's face, where the numbers and other graduations appear, is often called the chapter ring. Graduation in an instrument refers to the marking the instrument with indicators of a measurement

The clock face is so familiar that, particularly in the case of watches, the numbers are often omitted and replaced with undifferentiated hour marks. Occasionally markings of any sort are dispensed with, and the time is read by the angles of the hands. The face of the Movado "Museum Watch" is known for a single dot at the 12 o'clock position. Movado is a Swiss luxury Watch company whose name is Esperanto for "movement"

Historical development

Clocks existed before clock faces. The first mechanical clocks from 13th century Europe were striking clocks: their purpose was to ring bells upon the canonical hours, to call the public to prayer. A striking clock is a Clock that sounds the Hours audibly on a bell or Gong. Canonical hours are divisions of time developed by the Christian Church, serving as increments between the prescribed Prayers of the daily round These were erected as tower clocks in public places, to ensure that the bells were audible. A clock tower is a Tower built with one or more (often four Clock faces. It was not until these mechanical clocks were in place that their creators realized that their wheels could be used to drive an indicator on a dial on the outside of the tower, where it could be widely seen.

15th century rotating dial clock face, St. Mary's Church, Gdansk, Poland.

Before the late 15th century, a fixed hand (often a carving shaped like a hand) indicated the hour by pointing to numbers on a rotating dial; after this time the current convention of a rotating hand on a fixed dial was adopted. A convention is a set of agreed, stipulated or generally accepted Standards norms social norms or criteria, often taking the form of Minute hands (so named because they were the small or minute divisions of the hour) only came into regular use around 1690, after the invention of the pendulum increased the precision of time-telling enough to justify it. A pendulum is a mass that is attached to a pivot from which it can swing freely In some precision clocks a third hand, which rotated once a minute, was added in a separate subdial. This was called the 'second-minute' hand (because it measured the secondary minute divisions of the hour), which was shortened to 'second' hand. The convention of the hands moving clockwise evolved in imitation of the sundial. A clockwise motion is one that proceeds 'like the Clock 's hands' from the top to the right then down and then to the left and back to the top A sundial is a device that measures time by the position of the Sun. In the Northern hemisphere, where the clock face originated, the shadow of the gnomon on a sundial moves clockwise during the day. The gnomon is the part of a Sundial that casts the Shadow. Gnomon (γνώμων is an Ancient Greek word meaning "indicator" "one who ^[1] This was also why noon or 12 o'clock was conventionally located at the top of the dial.

Stylistic development

A ship's radio room wall clock during the age of Wireless telegraphy

Until the last quarter of the 17th century hour markings were etched into metal faces and the recesses filled with black wax. The term Wireless Telegraphy is a historic term used today as applied to early Radio Telegraph communications techniques and practices Subsequently, higher contrast and improved readability was achieved with white enamel plaques painted with black numbers. Initially, the numbers were printed on small, individual plaques mounted on a brass substructure. This was not a stylistic decision, rather enamel production technology had not yet achieved the ability to create large pieces of enamel. In a discussion of Material science, enamel (or vitreous enamel or porcelain enamel in U The "13 piece face" was an early attempt to create an entirely white enamel face. As the name suggests, it was composed of 13 enamel plaques: 12 numbered wedges fitted around a circle. The first single piece enamel faces, not unlike those in production today, began to appear c. 1735.

Footnotes