A pendulum clock is a clock that uses a pendulum, a swinging weight, as its timekeeping element. The advantage of a pendulum for timekeeping is that it is an approximate harmonic oscillator: It swings back and forth in a precise time interval dependent on its length, and resists swinging at other rates. From its invention in 1656 by Christiaan Huygens, inspired by Galileo Galilei, until the 1930s, the pendulum clock was the world's most precise timekeeper, accounting for its widespread use. Throughout the 18th and 19th centuries, pendulum clocks in homes, factories, offices, and railroad stations served as primary time standards for scheduling daily life, work shifts, and public transportation. Their greater accuracy allowed for the faster pace of life which was necessary for the Industrial Revolution. The home pendulum clock was replaced by less-expensive synchronous electric clocks in the 1930s and '40s. Pendulum clocks are now kept mostly for their decorative and antique value.
A carillon ( KARR-ə-lon, kə-RIL-yən) is a pitched percussion instrument that is played with a keyboard and consists of at least 23 bells. The bells are cast in bronze, hung in fixed suspension, and tuned in chromatic order so that they can be sounded harmoniously together. They are struck with clappers connected to a keyboard of wooden batons played with the hands and pedals played with the feet. Often housed in bell towers, carillons are usually owned by churches, universities, or municipalities. They can include an automatic system through which the time is announced and simple tunes are played throughout the day.
Sather Tower is a bell tower with clocks on its four faces on the campus of the University of California, Berkeley. It is more commonly known as The Campanile for its resemblance to the Campanile di San Marco in Venice. It is a recognizable symbol of the university.
A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day.
The Westminster Quarters, from its use at the Palace of Westminster, is a melody used by a set of four quarter bells to mark each quarter-hour. It is also known as the Westminster Chimes, Cambridge Quarters, or Cambridge Chimes, from its place of origin, the Church of St Mary the Great, Cambridge.
Harkness Tower is a masonry tower at Yale University in New Haven, Connecticut. Part of the Collegiate Gothic Memorial Quadrangle complex completed in 1922, it is named for Charles William Harkness, brother of Yale's largest benefactor, Edward Harkness.
A grandfather clock is a tall, freestanding, weight-driven pendulum clock, with the pendulum held inside the tower or waist of the case. Clocks of this style are commonly 1.8–2.4 metres (6–8 feet) tall with an enclosed pendulum and weights, suspended by either cables or chains, which have to be occasionally calibrated to keep the proper time. The case often features elaborately carved ornamentation on the hood, which surrounds and frames the dial, or clock face.
A doorbell is a signaling device typically placed near a door to a building's entrance. When a visitor presses a button, the bell rings inside the building, alerting the occupant to the presence of the visitor. Although the first doorbells were mechanical, activated by pulling a cord connected to a bell, modern doorbells are electric, operated by a pushbutton switch. Modern doorbells often incorporate intercoms and miniature video cameras to increase security.
First grade is the first year of formal or compulsory education. It is the first year of elementary school, and the first school year after kindergarten. Children in first grade are usually 6–7 years old.
An alarm clock or alarm is a clock that is designed to alert an individual or group of people at a specified time. The primary function of these clocks is to awaken people from their night's sleep or short naps; they can sometimes be used for other reminders as well. Most alarm clocks make sounds; some make light or vibration. Some have sensors to identify when a person is in a light stage of sleep, in order to avoid waking someone who is deeply asleep, which causes tiredness, even if the person has had adequate sleep. To turn off the sound or light, a button or handle on the clock is pressed; most clocks automatically turn off the alarm if left unattended long enough. A classic analog alarm clock has an extra hand or inset dial that is used to show the time at which the alarm will ring. Alarm clock functions are also used in mobile phones, watches, and computers.
A train whistle or air whistle is an audible signaling device on a steam or gas locomotive, used to warn that the train is approaching, and to communicate with rail workers. Modern diesel and electric locomotives primarily use a powerful air horn instead of a whistle as an audible warning device. However, the word whistle continues to be used by railroaders in referring to such signaling practices as "whistling off".
A repeater is a complication in a mechanical watch or clock that chimes the hours and often minutes at the press of a button. There are many types of repeater, from the simple repeater which merely strikes the number of hours, to the minute repeater which chimes the time down to the minute, using separate tones for hours, quarter hours, and minutes. They originated before widespread artificial illumination, to allow the time to be determined in the dark, and were also used by the visually impaired. Now they are mostly valued as expensive novelties by watch and clock enthusiasts. Repeaters should not be confused with striking clocks or watches, which do not strike on demand, but merely at regular intervals.
A striking clock is a clock that sounds the hours audibly on a bell, gong, or other audible device. In 12-hour striking, used most commonly in striking clocks today, the clock strikes once at 1:00 am, twice at 2:00 am, continuing in this way up to twelve times at 12:00 mid-day, then starts again, striking once at 1:00 pm, twice at 2:00 pm, up to twelve times at 12:00 midnight.
A senior prank, also known as muck-up day in Australia and the United Kingdom, is a type of organized prank by the senior class of a school, college, or university. They are often carried out at or near the end of the academic year and are part of school traditions. While most senior pranks are harmless, more severe pranks can include damage to school property and other crimes, which can result in disciplinary or even legal repercussions against the perpetrators.
A steam whistle is a device used to produce sound in the form of a whistle using live steam, which creates, projects, and amplifies its sound by acting as a vibrating system.
A chime or set of chimes is a carillon-like instrument, i.e. a pitched percussion instrument consisting of 22 or fewer bells. Chimes are primarily played with a keyboard, but can also be played with an Ellacombe apparatus. Chimes are often automated, in the past with mechanical drums connected to clocks and in the present with electronic action. Bellfounders often did not attempt to tune chime bells to the same precision as carillon bells. Chimes are defined as specifically having fewer than 23 bells to distinguish them from the carillon. American chimes usually have one to one and a half diatonic octaves. According to a recent count, there are over 1,300 existing chimes throughout the world. Almost all are in the Netherlands and the United States, with most of the remainder in Western European countries.
Big Ben is the common name for the Great Bell of the Great Clock of Westminster, and by extension to the clock tower and the clock itself. The Great Clock of Westminster is a striking clock with five bells. The clock tower is at the north end of the Palace of Westminster in London, England, and was originally known simply as the Clock Tower, but was renamed Elizabeth Tower in 2012 to mark the Diamond Jubilee of Elizabeth II.
A train horn is an air horn used as an audible warning device on diesel and electric-powered trains. Its primary purpose is to alert persons and animals to an oncoming train, especially when approaching a level crossing. They are often extremely loud, allowing them to be heard from great distances. They are also used for acknowledging signals given by railroad employees, such as during switching operations. For steam locomotives, the equivalent device is a train whistle.
The Senior Memorial Chime, known more commonly as the Altgeld Chimes, is a 15-bell chime in Altgeld Hall Tower on the central campus of the University of Illinois Urbana-Champaign, in Urbana, Illinois, United States.
Due to the COVID-19 pandemic in the United Kingdom, all secondary education examinations due to be held in 2020 were cancelled. As a result, an alternative method had to be designed and implemented at short notice to determine the qualification grades to be awarded to students for that year. A standardisation algorithm was produced in June 2020 by the regulator Ofqual in England, Qualifications Wales in Wales, Scottish Qualifications Authority in Scotland, and CCEA in Northern Ireland. The algorithm was designed to combat grade inflation, and was to be used to moderate the existing but unpublished centre-assessed grades for A-Level and GCSE students. After the A-Level grades were issued, and after criticism, Ofqual, with the support of HM Government, withdrew these grades. It issued all students the Centre Assessed Grades (CAGs), which had been produced by teachers as part of the process. The same ruling was applied to the awarding of GCSE grades, just a few days before they were issued: CAG-based grades were the ones released on results day.
