Many alarm clocks have radio receivers that can be set to start playing at specified times, and are known as clock radios. Some alarm clocks can set multiple alarms, a useful feature for couples who have different waking up schedules. A progressive alarm clock, still new in the market, can have different alarms for different times (see Next-Generation Alarms) and even play music of your choice. Most modern televisions, mobile phones and digital watches have alarm clock functions to turn on or make sounds at a specific time.
From the 14th century, some clock towers in Western Europe were also capable of chiming at a fixed time every day; the earliest of these was described by the Florentine writer Dante Alighieri in 1319.[8] The most famous original striking clock tower still standing is possibly the one in St Mark's Clocktower in St Mark's Square, Venice. The St Mark's Clock was assembled in 1493, by the famous clockmaker Gian Carlo Rainieri from Reggio Emilia, where his father Gian Paolo Rainieri had already constructed another famous device in 1481. In 1497, Simone Campanato moulded the great bell (h. 1,56 m., diameter m. 1,27), which was put on the top of the tower where it was alternatively beaten by the Due Mori (Two Moors), two bronze statues (h. 2,60) handling a hammer.

In addition to radio, recent clock radios have other music sources such as iPod, iPhone, and/or audio CD. When the alarm is triggered, it can play a set radio station or the music from a selected music source to awaken the sleeper. These models usually come with a dock for iPod/iPhone that also charges the device while it is docked. They can play FM/AM radio, iPod/iPhone or CD like a typical music player as well (without being triggered by the alarm function). A few popular models offer "nature sounds" like rain, forest, fire, sea, waterfall etc., in place of the buzzer.

The primary purpose of a clock is to display the time. Clocks may also have the facility to make a loud alert signal at a specified time, typically to waken a sleeper at a preset time; they are referred to as alarm clocks. The alarm may start at a low volume and become louder, or have the facility to be switched off for a few minutes then resume. Alarm clocks with visible indicators are sometimes used to indicate to children too young to read the time that the time for sleep has finished; they are sometimes called training clocks.
Besides the Chinese astronomical clock of Su Song in 1088 mentioned above, in Europe there were the clocks constructed by Richard of Wallingford in St Albans by 1336, and by Giovanni de Dondi in Padua from 1348 to 1364. They no longer exist, but detailed descriptions of their design and construction survive,[22][23] and modern reproductions have been made.[23] They illustrate how quickly the theory of the mechanical clock had been translated into practical constructions, and also that one of the many impulses to their development had been the desire of astronomers to investigate celestial phenomena.

A clock that looks good and runs smoothly instantly adds charm and functionality to your living space. For a fresh take on the traditional wall clock, consider this eye-catching design. Introducing Ribbonwood by Umbra Add a modern, minimalist twist to telling time. With Ribbonwood, you get a stylish piece of wall décor and a functional wall clock all-in-one. Made with natural beech wood that’s been shaped to resemble overlapping ribbons, this unique clock features contrasting hands that...
Time switches can be used to turn on anything that will awaken a sleeper, and can therefore be used as alarms. Lights, bells, and radio and TV sets can easily be used.[32] More elaborate devices have also been used, such as machines that automatically prepare tea or coffee. A sound is produced when the drink is ready, so the sleeper awakes to find the freshly brewed drink waiting.[33]
A: If your clock is waking you up too abruptly, pulling you out of REM sleep like Leo from a dream inside another dream, your body goes into a moderate level of shock. You’ll feel your heart kick up all of a sudden, because now you’re awake, and your body has been taken by surprise. You have to go from a resting heart rate of 40-50 BPM, back to a standard heart rate (or a little higher at first) of around 60-100 BPM
Here is a clock that will look great in any room in the house and it never needs a plug! This Water Clock is powered by ordinary tap water. Never needs batteries or electricity. Just fill this Water clock with water and you are on your way to more eco-friendly home. After about 6 months to a year you may need to dump the water out (your can pour it into a plant) and refill. The clock will remember the time as you do so. It even has an alarm. Great for traveling as well. Why would you ever use...
The Howard Miller Brohman 625-618 Large Wall Clock has a brushed, warm brown finish and metallic undertones. At 34" in diameter with a 22" aged dial this clock will fit just about any decor. With large Roman numerals and black hands this clock will be a favorite for years to come. Highly accurate quartz movement requires one AA battery (Not Included).
During the 15th and 16th centuries, clockmaking flourished, particularly in the metalworking towns of Nuremberg and Augsburg, and in Blois, France. Some of the more basic table clocks have only one time-keeping hand, with the dial between the hour markers being divided into four equal parts making the clocks readable to the nearest 15 minutes. Other clocks were exhibitions of craftsmanship and skill, incorporating astronomical indicators and musical movements. The cross-beat escapement was invented in 1584 by Jost Bürgi, who also developed the remontoire. Bürgi's clocks were a great improvement in accuracy as they were correct to within a minute a day.[35][36] These clocks helped the 16th-century astronomer Tycho Brahe to observe astronomical events with much greater precision than before.[citation needed][how?]
Get the reliability you need without sacrificing style. Get the reliability you need without sacrificing style. The Analog Quartz Mantel Alarm Clock from La Crosse Clock Co. is a traditional beeping alarm clock. It has the added bonus of luminous hands for easy nighttime viewing. The classic design features a black matted frame with black metal hands and ...  More + Product Details Close

Although the mechanisms they use vary, all oscillating clocks, mechanical, digital and atomic, work similarly and can be divided into analogous parts.[64][65][66] They consist of an object that repeats the same motion over and over again, an oscillator, with a precisely constant time interval between each repetition, or 'beat'. Attached to the oscillator is a controller device, which sustains the oscillator's motion by replacing the energy it loses to friction, and converts its oscillations into a series of pulses. The pulses are then counted by some type of counter, and the number of counts is converted into convenient units, usually seconds, minutes, hours, etc. Finally some kind of indicator displays the result in human readable form.
Water clocks, also known as clepsydrae (sg: clepsydra), along with the sundials, are possibly the oldest time-measuring instruments, with the only exceptions being the vertical gnomon and the day counting tally stick.[9] Given their great antiquity, where and when they first existed is not known and perhaps unknowable. The bowl-shaped outflow is the simplest form of a water clock and is known to have existed in Babylon and in Egypt around the 16th century BC. Other regions of the world, including India and China, also have early evidence of water clocks, but the earliest dates are less certain. Some authors, however, write about water clocks appearing as early as 4000 BC in these regions of the world.[10]
“Love how simple this digital timer is. I travel a lot, and it’s small enough to put in my purse. The off button is convenient because it keeps the buttons from being pressed while stored away and conserves the battery, but when you turn it back on, your setting are stored so no need to reset [each] time. … [There’s just the] clock, alarm, snooze, on/off. The smaller and simpler the better when I’m traveling.”