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.
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
This color-changing option features a radio, built-in wake-up tones, Bluetooth music streaming (so you can wake up to your favorite playlist), and USB-charging capacity to keep your phone juiced. You can preset two alarms, cycle through colors, and snooze, and even use the alarm clock's speakerphone and microphone functions to answer phone calls from paired devices. Basically, this clock does everything except your laundry.

The tick duration must be positive. If it has a part smaller than a whole millisecond, then the whole duration must divide into one second without leaving a remainder. All normal tick durations will match these criteria, including any multiple of hours, minutes, seconds and milliseconds, and sensible nanosecond durations, such as 20ns, 250,000ns and 500,000ns.


Never squint to see what time it is again, especially when you're waking up 20 times in the middle of the night to, you know, see exactly what time it is. We love the projection feature that displays the time on your wall or ceiling for easy viewing. Plus, it'll even toss up the temperature — so you'll already know what you should wear to work before you even get out of bed.
Offer up eye-popping appeal on your walls with this absolutely striking wall clock, the perfect finishing touch to your factory-inspired ensemble. Fashioned from welded steel and featuring a deep black finish, this understated and chic clock lends a touch of simple style to your look, while its 45" diameter ensures it will make a big impact wherever you decide to hang it. Hang it up over trellis-print wallpaper in the living room to let the patterns show through this clock's openwork design, or...

The advantage of a harmonic oscillator over other forms of oscillator is that it employs resonance to vibrate at a precise natural resonant frequency or 'beat' dependent only on its physical characteristics, and resists vibrating at other rates. The possible precision achievable by a harmonic oscillator is measured by a parameter called its Q,[68][69] or quality factor, which increases (other things being equal) with its resonant frequency.[70] This is why there has been a long term trend toward higher frequency oscillators in clocks. Balance wheels and pendulums always include a means of adjusting the rate of the timepiece. Quartz timepieces sometimes include a rate screw that adjusts a capacitor for that purpose. Atomic clocks are primary standards, and their rate cannot be adjusted.


Mixing modern minimalism with industrial influence, this round 28" wall clock is as much a decorative accent as it is a practical timepiece. Crafted from metal, it showcases sizable Roman numerals and small spade-style hands to help you keep an eye on the hour. Its black and gold finish gives it an antiqued appearance, while its open design ensures it won’t overwhelm your arrangement. This piece requires two AA batteries (not included) to operate.
The Howard Miller Spokane 15.75" Wall Clock is a piece of classic design and features. This simple yet functional timepiece has a brushed aluminum finish. This round shape clock is very convenient and can be mounted on any wall of your home. This wall clock can be used for residential as well as commercial use as it has simple and subtle. This round wall clock from Spokane has a silver finished case with white background for ease at readability. This wall clock is numbered and features Arabic...
Molded by mid-century modern style, this 38" wall clock brings a bit of bold flair to any space in your home. Its generous size helps it grab glances (and compliments!) from guests, while its open and numberless design gives it a minimalist feel. Crafted from metal, this round silhouette sports a gold finish with silver-finished hands in the center for subtle contrast. Two AA batteries (not included) are required to operate.
The iHome has more in common with a sound system than an alarm clock, but this all-in-one device is perfect for anyone who’s looking to declutter their nightstand on a budget. Along with having a good alarm clock to wake you up every morning, the iHome also features Bluetooth connectivity and FM radio, meaning you’ll no longer have to deal with pesky USB chargers before you go to bed. The translucent cabinet and display changes color with the touch of a button, so you can wake up to your favorite colors.
A water-powered cogwheel clock was created in China in AD 725 by Yi Xing and Liang Lingzan. This is not considered an escapement mechanism clock as it was unidirectional, the Song dynasty polymath and genius Su Song (1020–1101) incorporated it into his monumental innovation of the astronomical clock-tower of Kaifeng in 1088.[19][page needed] His astronomical clock and rotating armillary sphere still relied on the use of either flowing water during the spring, summer, autumn seasons and liquid mercury during the freezing temperature of winter (i.e. hydraulics). A mercury clock, described in the Libros del saber, a Spanish work from 1277 consisting of translations and paraphrases of Arabic works, is sometimes quoted as evidence for Muslim knowledge of a mechanical clock. A mercury-powered cogwheel clock was created by Ibn Khalaf al-Muradi[20][21]
A minimalist twist on the traditional wall clock. Resolve to find contentment with the time you are given, without obsessing over the numbers. Feel things you have never felt before. Experience different points of view. Make the best of it. Live a life you are proud of. Discover the value of time with The Adam Schwoeppe Minimalist Circle Clock, an elegant eclectic timepiece. Revitalize your home decor as time passes silently with this modern black circle clock.

Showcasing the time, date, and weather, this clock is an essential for any desk. No need to lift your arm and look at your watch or light up your phone screen, this 0.3'' H x 3.7'' W x 1.5'' D design is an easy way to get the info you need. A vibrant blue backlight keeps it illuminated (requiring the power of a AA battery), while a plastic frame allows it to stand upright.


Spring-driven clocks appeared during the 15th century,[25][26][27] although they are often erroneously credited to Nuremberg watchmaker Peter Henlein (or Henle, or Hele) around 1511.[28][29][30] The earliest existing spring driven clock is the chamber clock given to Phillip the Good, Duke of Burgundy, around 1430, now in the Germanisches Nationalmuseum.[4] Spring power presented clockmakers with a new problem: how to keep the clock movement running at a constant rate as the spring ran down. This resulted in the invention of the stackfreed and the fusee in the 15th century, and many other innovations, down to the invention of the modern going barrel in 1760.
Rise and shine, rebel. This Stormtrooper comes to you, bringing news of a peace proposal with the empire. See those bright numbers displayed brilliantly on its LCD screen? That means it's time to go. Adjustable arms point toward the door, beckoning for you to make haste. But before you head off to save the galaxy, you might want to turn your Lego alarm clock off first. Plus, if you're a Darth Vader fan, you can get this alarm clock with him, too!

Keep tabs on the time while creating an eye-catching focal point in your ensemble with this stylish wall clock. Crafted from metal, it features a circular silhouette with a black finish around the periphery while its Roman numerals and two spade hands inside are coated in an antique copper coloring. It only needs one AA battery to operate (not included), and is suitable for indoor and outdoor spaces alike. Measures 13.75'' W x 13.75'' H x 2'' D.

A perfect piece for nightstands and home office desks, this radio alarm clock tunes to your favorite stations as it keeps an eye on the hour. Its bright red LED numbers are easy to read from afar, while the repeating nine-minute snooze is sure to become your new best friend on lazy Sunday mornings. This digital clock includes memory for up to 20 radio stations and includes an audio input for smartphones and MP3 players. Though this radio plugs into your wall, it also runs on two AAA batteries...


Hopefully, you don’t have sensitive eyes. Get ready to have over 100 lumens pull up on you like the flashlight of a police officer on a Saturday night. One thing’s for sure—it’s going to wake you up, and keep you up. This is a nature sounds alarm clock to boot, so you’ll feel like you’re in the middle of the meadow when it goes off. A very bright meadow. NakaLight Wake Up will gradually light up a half hour before you awaken to ease you out of sleep.
Incorporating clocks into your home design is a way to better keep track of time and can make a unique style statement in your home. Clocks work well in every room of your home, from the living room to the bedroom. You can find wall clocks, mantel clocks, grandfather clocks and outdoor clocks that fit your personal style. Large wall clocks look beautiful in your home and are elegant focal piece in your living room. Make sure that you match the style and texture of your clock to the décor in your home. You can use stylish clocks in your home to accessorize thematic designs and emphasize specific areas of your home.
Never squint to see what time it is again, especially when you're waking up 20 times in the middle of the night to, you know, see exactly what time it is. We love the projection feature that displays the time on your wall or ceiling for easy viewing. Plus, it'll even toss up the temperature — so you'll already know what you should wear to work before you even get out of bed.
Stay on schedule and charge a range of devices with this innovative iHome dual-alarm clock. Place your compatible smartphone on top of the Qi-certified device for swift wireless charging, or plug your phone into the clock’s handy powered USB port. This iHome dual-alarm clock incorporates NFC technology, so you can connect an array of Bluetooth-enabled devices with a quick touch.
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]
In a master clock system, electricity is used to give direct impulses to the pendulum, which in turn causes the clock’s gear train to move, or to lift a lever after it has imparted an impulse to the pendulum. In various modern master clocks the pendulum operates a light count wheel that turns through the pitch of one tooth every double swing and is arranged to release a lever every half minute. This lever gives an impulse to the pendulum and is then restored to its original position by an electromagnet. The pulse of current that operates the electromagnet can also be transmitted to a series of distant dials, or slave clocks, advancing the hands of each through the space of a half minute. Thus, a master clock can control scores of dials in a large group of buildings, as well as such other apparatus as time recorders and sirens.

Early clock dials did not indicate minutes and seconds. A clock with a dial indicating minutes was illustrated in a 1475 manuscript by Paulus Almanus,[31] and some 15th-century clocks in Germany indicated minutes and seconds.[32] An early record of a seconds hand on a clock dates back to about 1560 on a clock now in the Fremersdorf collection.[33]:417–418[34]
The Howard Miller Spokane 15.75" Wall Clock is a piece of classic design and features. This simple yet functional timepiece has a brushed aluminum finish. This round shape clock is very convenient and can be mounted on any wall of your home. This wall clock can be used for residential as well as commercial use as it has simple and subtle. This round wall clock from Spokane has a silver finished case with white background for ease at readability. This wall clock is numbered and features Arabic...

A vintaged take on traditional style, this alarm clock brings time-honored style to any space, without breaking the bank. Crafted from metal, this analog alarm clock showcasing a round face sitting atop a molded base. Giving this piece a distinctive look is an antiqued face, outfitted with glow-in-the-dark hour and minute hands. Black and neutral hues round out this clock's color palette, accented with distressed details. Measured at under half-a-foot tall and wide, this lightweight clock is...

This special 82nd Anniversary Edition Contemporary wall clock is one our more popular pendulum chiming wall clocks and features a white dial with black Roman numerals and a brushed nickel bezel. A spun nickel pendulum bob is suspended in front of a mirrored back. Finished in Black Satin. One Year Warranty. Quartz, triple chime Harmonic movement plays your choice of Westminster, Ave Maria, or Bim-Bam chimes with volume control and automatic nighttime chime shut-off option.


In Europe, between 1280 and 1320, there is an increase in the number of references to clocks and horologes in church records, and this probably indicates that a new type of clock mechanism had been devised. Existing clock mechanisms that used water power were being adapted to take their driving power from falling weights. This power was controlled by some form of oscillating mechanism, probably derived from existing bell-ringing or alarm devices. This controlled release of power—the escapement—marks the beginning of the true mechanical clock, which differed from the previously mentioned cogwheel clocks. Verge escapement mechanism derived in the surge of true mechanical clocks, which didn't need any kind of fluid power, like water or mercury, to work.
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 Ribbon Wall Clock by Umbra Add a modern, minimalist twist to telling time. With Ribbon, you get a stylish piece of wall décor and a functional wall clock all-in-one. Made with high-quality metal that’s been shaped to resemble overlapping ribbons, this unique clock features contrasting hands...
Sounds pretty self explanatory, right? You have to get up, position two thumbs on the bottom of the screen, and turn around according to the predesignated amount of spins. You’ll actually have to jerk yourself around, and by the end of it, you’ll look at the bed and say, “Well, I’m already up.” At least, that’s the hope of the app developers. This one comes in handy if paired with louder alarm clocks, as well.

This alarm clock uses scent cartridges to wake you up to the smell of your favorite things, from bacon (!!!) to sweet peach. You can purchase any variety of cartridges you'd like (scents include bacon, cappuccino, mint, strawberry candy, banana, and sweet peach), but your initial purchase will come with one bacon capsule. Each cartridge contains 30 wake-ups.


For some scientific work timing of the utmost accuracy is essential. It is also necessary to have a standard of the maximum accuracy against which working clocks can be calibrated. An ideal clock would give the time to unlimited accuracy, but this is not realisable. Many physical processes, in particular including some transitions between atomic energy levels, occur at exceedingly stable frequency; counting cycles of such a process can give a very accurate and consistent time—clocks which work this way are usually called atomic clocks. Such clocks are typically large, very expensive, require a controlled environment, and are far more accurate than required for most purposes; they are typically used in a standards laboratory.
This metal wire case wall clock is finished in antique black with antique gold highlights. The pendulum bob, with matching finish, is an open circle, suspended on a metal pendulum. A black bezel surrounds the convex acrylic crystal. The dial features an antique Antique Red background with gold Arabic numerals and Antique gold spade hands. Quartz, non-chiming battery operated movement. One Year Warranty.
Howard Miller Carmen wrought iron wall clock with cast decorative corner ornaments finished in warm gray, dusty wax highlights. Windsor Cherry finished wood columns provide a warm accent on each side. Convex glass covers the antique dial, which offers black Roman numerals and serpentine hands. The swinging pendulum is finished in warm gray with dusty wax highlights to match the case. Quartz, non-chiming battery operated movement.
Now, RCA Digital Alarm Clock is pretty basic, but for some of us, that’s all we need, right? With a bright, beaming red LED display, you’re certain to rub your eyes and wonder what weird light is pulsating from your nightstand. There’s an alarm indicator and the classic AM/PM light that we all remember from early-2000 models. You can do something different from your late 1990s-inspired clock, and that is change the brightness levels so you don’t completely burn out your retinas.
Simple clocks intended mainly for notification were installed in towers, and did not always require faces or hands. They would have announced the canonical hours or intervals between set times of prayer. Canonical hours varied in length as the times of sunrise and sunset shifted. The more sophisticated astronomical clocks would have had moving dials or hands, and would have shown the time in various time systems, including Italian hours, canonical hours, and time as measured by astronomers at the time. Both styles of clock started acquiring extravagant features such as automata.
This 24" large metal Large Wall Clock is finished in a dark rubbed bronze with aged bronze accents at the 3, 6, 9 and 12 positions. The aged dial features a subtle center pattern, aged black Roman numerals, black spade hour and minute hands and a convex glass crystal. A twisted metal ring frames the dial. Quartz, battery operated movement. One year warranty and Free Shipping.
As stylish as it is functional, this lovely clock lends a touch of charm and classic appeal to your tabletop display. A traditional design, it showcases a rounded frame with a pedestal base and a solid black finish. The neutral-toned clock face is accented with black Roman numeral numbering and three thin black hands. Crafted from plastic, it is a budget-friendly choice. It also features a beeping alarm for added convenience.
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