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.

A well-made large wall clock that looks good and runs smoothly can bring charm and functionality to any space. For a fresh take on the traditional clock, consider this eye-catching design... Introducing Rimwood by Umbra Every Umbra wall clock is tested in our factory before shipping to ensure it works perfectly. This, coupled with a sleek and modern design, ensures you’re getting a clock that not only tells time accurately but also looks great. This classically-inspired clock has a truly...

You can choose from an analog styled clock to a digital one. Our alarm clocks can vary from old, retro, 1950 styled clocks to modern 2013. Depending on your desire, we have wind up alarm clocks, clocks that do or do not tick, or clocks with or without a built in radio. We have clocks for children, clocks that run on battery, or ones that plug directly into an outlet.

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).
Special features beyond simply keeping time can be either practical or decorative. Often found in the kitchen or other busy room, some digital clocks can show readings of the indoor or outdoor temperature, display the date, and have the capacity to set an alarm or timer. A swinging pendulum is most commonly found on fancier wood and metal clocks, though some novelty styles also feature a pendulum.

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.
This looks like a Death Star droid out of a Star Wars movie, but it gets the job done with the tricks up its sleeve. Charge your phone and your tablet at the same time with two power outlets and two USB ports. The alarm clock feature is simple, and while it also projects your tunes via Bluetooth audio, it comes with a surge protector. That’s right; no freak lightning storm is allowed to hold you back. CubieBlue Charging Bluetooth Speaker is still going to work when you plug it back in (even if you threw it across the room).
Many devices can be used to mark passage of time without respect to reference time (time of day, minutes, etc.) and can be useful for measuring duration or intervals. Examples of such duration timers are candle clocks, incense clocks and the hourglass. Both the candle clock and the incense clock work on the same principle wherein the consumption of resources is more or less constant allowing reasonably precise and repeatable estimates of time passages. In the hourglass, fine sand pouring through a tiny hole at a constant rate indicates an arbitrary, predetermined, passage of time. The resource is not consumed but re-used.

This is the number-one selling kid's clock on Amazon, with more than 2,500 reviews. Parents rave about the restoration of their sleep time. Many parents say it "saved me from my early riser! Life changing!" Even parents of older children with developmental delays found the clock very useful in indicating to non-readers when it's okay to get up, and when it's not.

This farmhouse wall clock measures 30 in. across This farmhouse wall clock measures 30 in. across the face and features horizontal cedar wood slats a white distressed finish hand painted black Roman numerals in a Poster Condensed font and an inner accent ring with individual hour marks. It includes a high torque quartz movement antique-style spade hands and ...  More + Product Details Close
This dual tone wall clock features a handsome Rustic Cherry finish with a contrasting Vintage Umber inset panel. The wood stick moving pendulum features a spun brass-finished bob. Beneath a convex glass crystal, the dial features a two color wood-tone dial with gold Arabic numerals and aged brass-tone spade hands. Finished in distressed Rustic Cherry on select hardwoods and veneers. Quartz, non-chiming battery operated movement.
Versatile style abounds with this wood and metal wall clock, showcasing a wine barrel-inspired design. Its plank details pair perfectly with rustic decor while its rivet accents match with industrial options and factory-inspired furniture. Add it to the dining room to complement a cozy loft ensemble or use it to round out a bold boho look in the den. Its round silhouette adds traditional flair to both formal and casual aesthetics while its natural hues blend effortlessly into any color palette....
Sure, it looks harmless, but Poweriever Bluetooth 32L will blast your tunes until there is no tomorrow. When you want to connect to your alarm clock to play your favorite music, you’ve met your match in terms of an alarm clock. You get a reactive light bar to turn on when you touch it, as well as a rechargeable battery that ensures you won’t be left without your alarm, even when there’s a power failure in the middle of the night. Your boss doesn’t care—you still have to get in on time. Make every minute count with this premier electric alarm clock.
This Mission style wall clock is finished in a Mission Oak dark finish. A parchment dial features dark brown numerals and hands. Decorative, wooden moldings frame the dial. Circular brushed brass swinging pendulum is antiqued and framed with wooden, reeded grilles. Quartz, dual chime movement plays Westminster or Ave Maria chimes, and features volume control and automatic nighttime shut-off option. Shadow collection - matching floor clock available. Size: H. 32-1/2" W.16-3/4" D.6"
The Homedics SoundSpa Digital FM Tabletop Clock with time projection gives you the power to create a soothing, relaxing sleep environment. Choose from eight peaceful relaxation sounds including ocean, white noise, brook, rainforest, thunder, rain, fan, campfire, or simply switch on the radio. The SoundSpa Digital FM Tabletop Clock comes with the option of time projection and a soothing blue light.

Keep track of time and exude antiqued style with this bold 24-inch oversized wall clock. Crafted from metal and wood, this round analog clock operates on quartz crystal movement and is embellished with a white background and black needles. Roman numerals lend a traditional touch, and small geometric details add extra dimension to the piece. Use this piece to help create a chic French countryside aesthetic in your kitchen. Start by painting the walls a light gray or beige tone with white trim....
A major stimulus to improving the accuracy and reliability of clocks was the importance of precise time-keeping for navigation. The position of a ship at sea could be determined with reasonable accuracy if a navigator could refer to a clock that lost or gained less than about 10 seconds per day. This clock could not contain a pendulum, which would be virtually useless on a rocking ship. In 1714, the British government offered large financial rewards to the value of 20,000 pounds,[42] for anyone who could determine longitude accurately. John Harrison, who dedicated his life to improving the accuracy of his clocks, later received considerable sums under the Longitude Act.
Not just for keeping your eye on the hour, this eye-catching wall clock lends a touch of retro flair to your ensemble in seconds. Measuring 9.5'' in diameter (so you know it'll fit just about anywhere), this piece pairs a glossy iron frame with a traditional analog dial. This product requires one AA battery to operate, which is not included. The manufacturer for this item provides a limited one-year warranty.
Acadia finish on select hardwoods and veneers is heavily distressed by scribes, and worm holes for a natural, rustic appearance — inspired by the natural yet rustic nature of reclaimed woods in beautiful patinas and burnished details. Features a multi-tiered flat top, distinctive columns with corbels frame the door. Circular spun antique nickel-finished dial with black Roman numerals, hour markers, and hands. Antique nickel-finished lyre pendulum. Quartz, battery-operated, triple-chime Harmonic movement plays choice of full Westminster or Ave Maria chimes with strike on the hour with 1/4, 1/2, and 3/4 chimes accordingly; Westminster chime and strike on the hour only; or Bim Bam chime on the hour only. Volume control and automatic nighttime chime shut-off option. Powered by two C sized batteries. One year warranty and Free Shipping
Bring bold, eye-popping appeal to your walls with this absolutely striking wall clock, the perfect finishing touch to your industrial-inspired ensemble. Crafted 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 39" diameter ensures it will make a big impact wherever you decide to hang it. Hang it up over muted stripe wallpaper in the living room to let the patterns show through this clock's openwork design...

Now this is an alarm clock for the heaviest sleeper. If you're the type who sleeps through anything — thunderstorms, loud neighbors, earthquakes, the zombie apocalypse — you've finally met your match. Sonic Alert's Sonic Bomb Alarm Clock doesn't just rely on its 113-decibel alarm to pry your eyelids open (for comparison, that's about the same decibel level as a car horn or snow blower going off in your ear), it also has a shaker device that slips underneath your mattress or pillow to jiggle you awake, and red flashing lights that trigger with the alarm.


Certainly not just for telling time, wall clocks are perfect for adding artful appeal to your kitchen wall or acting as a focal point above the living room mantel. Take this one for example: a true traditional, its Roman numeral dial is accented by a world map detailing the face. Crafted from plastic, its frame offers more of a metal-inspired look with molded trim and a bronze finish. Requires one AA battery.
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.
Small in size but striking in style, this eye-catching wall clock brings a dash of contemporary flair to any arrangement in your home. Showcasing a sunburst silhouette measuring 20" in diameter, this round silver-finished design is crafted with an iron and mirrored frame comprised of black spokes with orb-like accents. A petite glass clock face with sword-style hands sits in the center, allowing you to keep an eye on the hour in any room.
Exuding vintage appeal, this striking oversize wall clock rounds out rustic ensembles or lends a timeworn touch to modern spaces. Encased in wrought iron, this design features a wood face bearing distressed details and roman numerals tied together by spade-style hands. One AA battery (not included) keeps this design keeping time. Measuring 32'' W x 32'' H x 1'' D, it's sure to grab glances no matter where it's placed.

Clocks aren't just for telling time! Take this one for example: artful with its understated analog dial, this piece is perfect lending an upscale feel to your living room look or kitchen ensemble. Measuring 16'' circular, its frame features a glass design accented by a shiny chrome center and openwork hands to mark the hour. This product required one AA battery to operate, which is not included. Suitable for indoor use only.
Scientific studies on sleep having shown that sleep stage at awakening is an important factor in amplifying sleep inertia. Alarm clocks involving sleep stage monitoring appeared on the market in 2005.[22] The alarm clocks use sensing technologies such as EEG electrodes and accelerometers to wake people from sleep.[23][24]Dawn simulators are another technology meant to mediate these effects.[25]
Go to bed with positive thoughts. Tell yourself, “I want to get up early because…” and then, actually do it. Sleep studies happen all the time, and they tell us what exterior activities are affecting our dreams, our nightmares, etc., and talking to yourself as you drift off to bed has been proven to work. If you’re looking forward to something in the morning, tell yourself about it, and your body will hold onto that through the night.
Clockmakers developed their art in various ways. Building smaller clocks was a technical challenge, as was improving accuracy and reliability. Clocks could be impressive showpieces to demonstrate skilled craftsmanship, or less expensive, mass-produced items for domestic use. The escapement in particular was an important factor affecting the clock's accuracy, so many different mechanisms were tried.

Certainly not just for telling time, wall clocks are perfect for adding artful appeal to your kitchen wall or acting as a focal point above the living room mantel. Take this one for example: crafted from metal, its frame features an openwork design and a black finish for a look that fits right into traditional abodes and modern farmhouses alike. Measures about 30'' in diameter. Requires one AA battery to operate.
Alarmclocksonline.com can also be a great place to find a gift for a loved one or a coworker. With our vast assortment of clocks, you can find the perfect gift for whomever it may be. Get your husband that new mp3 dock he's been hoping for, your coworker a nice digital clock to put on his desk, or grandma a new large faced alarm clock so that she can read it without difficulty. The options are endless.
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]
You don't have to use all of those features, however. You can set them in a variety of combinations, or even turn all of them off except for the flashing red lights. You can also set the length of the alarm's ring from one to 60 minutes, and choose a snooze option from one to 30 minutes. Plus, the clock has dual alarms, so both you and your partner can have different wake-up times.
Antique styling in a two-tone wall clock features a Worn Black finish with red undertones and a contrasting Antique Red inset panel. Beneath a convex glass crystal, the dial features an Antique Red background with gold Arabic numerals and aged brass-tone spade hands. The wood stick pendulum features a spun brass-finished bob. Finished in Worn Black on select materials, hardwoods and veneers. Quartz, non-chiming battery operated movement.

There’s a lot of science when it comes to sleeping, and there’s never a short supply of sleep-related tests going on. One of our favorite electronic brands here on Gear Hungry has made the most effective clock (in our humble opinion), and it’s the #8 pick: Philips Wake-Up HF3505. Slow light build mimics the sunrise, and gently pulls you out of a sleep-like trance before hitting you with some serious sound. Between price, effectiveness, and the fact that we didn’t have to chase it around the room (sorry Clocky, we’re not morning people), we absolutely loved this one.


The origin of the all-mechanical escapement clock is unknown; the first such devices may have been invented and used in monasteries to toll a bell that called the monks to prayers. The first mechanical clocks to which clear references exist were large, weight-driven machines fitted into towers and known today as turret clocks. These early devices struck only the hours and did not have hands or a dial.
Improve independence with this Reminder Rosie personal voice reminder clock. It lets you schedule reminders for your loved one, letting them know what to do and when to do it, which helps seniors maintain independence for as long as possible. This Reminder Rosie alarm clock with personal voice reminder has a senior-friendly clock interface with an enlarged digital display.
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