How the Bulova Precisionist Works

Before we dive into the question of accuracy, let's take a second to get philosophical. Time measurement, after all, is something of an arbitrary construct. The seconds, minutes and hours we use to track duration are basically agreed-upon standards that humankind has employed to represent our march from the past into the future. Existence would not stop if we chose to stop tracking time in such a precise matter -- we could function just fine if our main time measurement consisted of sunrise, sunset and the position of the sun in between. A deep dive into the nature of time digs into such sticky wickets as multidimensionality, time travel and the nature of the universe. But for those of us inclined toward more concrete discussions, timepieces offer a more manageable topic [source: Biba].

Somewhere along the line, our ancestors decided that it was useful to track measured units of time. It may have been a pre-Egyptian noble or scholar who first noticed the steady march of shadows on a sunny day, but sundials -- the earliest timepieces -- have been recovered from archeological sites dating back to 800 B.C. [source: Gascoigne].

Modern watches and clocks work using principles that first came into widespread use in the middle of the 17th century: A resonator, which is a device such as a pendulum, spring-driven flywheel or electrified quartz crystal, oscillates, which means it vibrates or swings back and forth at a consistent, measurable rate. A timepiece will use gears, cams, electric circuits or a combination thereof to translate that oscillation into the measured movement of the clock's hands or a digital readout of the time [sources: Gascoigne, DiFranco].

For example, a grandfather clock may have a pendulum designed to swing from one side to the other every second. That motion momentarily releases a spring in the clock's mechanism, allowing the second, minute and hour hands to progress by their respective distances around the clock face. Suppose, now, that your clock has a pendulum that swings every half-second, doubling its oscillation. Your clock can now track half-seconds, giving the hands a smoother motion and allowing you to adjust it with a finer degree of precision. Take this concept, replace the pendulum with an object that oscillates at an extremely high frequency -- multiple times per second -- and you have the makings of a modern timepiece.

High-end watches can vary in accuracy depending on their mechanisms. Watch manufacturer Seiko claims its Spring Drive -- an electrically adjusted automatic mechanism -- varies by no more than one second per day, for example. Breitling, which markets its watches as pinnacle-of-performance timepieces for aviators and sailors, bills its automatics as meeting the Swiss Official Chronometer Testing Institute (COSC) standard for daily variation: no more than four seconds fast or six seconds slow per day. Quartz watches -- even relatively inexpensive ones -- can be expected to vary or drift by one second or less over the course of 24 hours [source: Lombardi].

The Bulova Precisionist has a claimed accuracy of 10 seconds of variation per year, drifting less in one month than a decent quartz watch might vary in a day. That may sound very accurate, and may be totally acceptable for most users. But wristwatches as a whole can't hold a candle to the mother of all accurate timekeepers: atomic clocks.

Forget pendulums; these precision machines use a variety of methods to measure the inherent oscillation of individual atoms. Working as tiny resonators, atoms vibrate at extremely high frequencies; Cesium atoms, for example, resonate at 9,192,631,770 hertz, or cycles per second. Atomic oscillation is also very consistent: Researchers behind a London-based clock using the so-called Cesium fountain process say that their machine is accurate to within two 10 million billionths of a second. Granted, the clock suffers from the inherent problem with atomic clocks from a consumer standpoint: they're large, sterile arrays of chambers, tubes, wires and scaffolds -- not something that would look nice on your wrist, and not exactly an affordable item available at the corner drugstore [source: Loftus]. But it's nice to know the gold standard when you're talking about time. (Learn more about atomic clocks in our article, How Atomic Clocks Work.)

The Bulova Precisionist is nowhere near as accurate as an atomic clock, but it does hold its own against other wristwatches in its price range. Read on to learn how the watchmaker squeezes this level of precision out of what is essentially an accurized quartz movement.

At its heart, the Precisionist mechanism uses tried-and-true quartz crystal technology: A carefully measured electrical current energizes a quartz crystal shaped like a tuning fork, which begins to oscillate at a particular frequency. This vibration creates electrical pulses at a consistent rate; the watch's integrated circuits use those pulses to trigger the watch motor. The motor, in turn, moves the gears, and thus the hands, a tiny distance with each pulse. (To learn more about the process, check out our article on How Quartz Watches Work.)

This mechanism overcomes a number of the problems faced by manual and self-winding watches, most notably the dependence on a delicate balance of wheels and springs. These precise components can be affected by gravity and strong electromagnetic fields, and they lose accuracy if not regularly cleaned and tuned. But quartz watches aren't invincible; beyond the need to replace the battery over time, the mechanisms hinge on the integrity of a tiny quartz tuning fork. Change the fork's temperature or contaminate its surface with even a little dirt or dust, and its oscillating frequency can change, throwing off the entire system [source: DiFranco].

The Precisionist uses a pair of tech tricks to overcome the quartz mechanism's weak points. First, its crystal is unique: most quartz watches use crystals shaped into two-pronged tuning forks, but the Precisionist literally goes one better with a three-pronged fork that the company claims can oscillate at 262.144 kilohertz (or 16 beats per second), about eight times faster than the 32.768 kilohertz (about 1 to 2 beats per second) that is the typical frequency for quartz oscillators. For comparison, the balance wheels of most mechanical watches oscillate at frequencies of 8 to 10 beats per second. Like a microscope being able to show more detail at 100X magnification than at 20X, the higher-frequency oscillation means the watch's processor can measure smaller fractions of each second, giving it more precise data to translate into the hands' movement [sources: Lombardi; Arnstein].

Bulova engineers tackled the problem of temperature fluctuation by adding temperature regulation to the Precisionist's circuitry. The circuitry in the watch essentially senses temperature changes and adapts to corresponding changes in the quartz crystal's electric pulses. It's a small adjustment that might seem too miniscule to bother with, but tiny changes in pulse strength at the crystal's high oscillation frequency can add up to accuracy-killing deviations as the temperature changes [sources: Lombardi; DiFranco].

As of Spring 2012, Bulova offered the Precisionist movement in six style collections ranging from sporty to dressy with prices ranging from about $300 to $900. For the most part, the collections target fashion-conscious consumers, with the major difference among the styles involving face shapes, engravings, colors and material selections. These range from slim stainless steel cases with leather straps, mother-of-pearl inlays and diamond accents to chunky titanium cases with ballistic fabric straps and carbon fiber inlays.

Most of the watches are water resistant to about 100 feet (30 meters) -- although one might find it hard to imagine taking the diamond-studded designs anywhere near a pool, let alone an ocean. The Champlain collection incorporates screw-back cases and extra gaskets to push the water resistance to about 900 feet (300 meters), making them suitable for use by divers [source: Bulova].

The Bulova Watch Company is employing new-to-the-market ideas in the Precisionist mechanism, but the company itself is no spring chicken. It has been in existence since 1875, and launched its first line of wristwatches in 1919 to respond to the demand of soldiers in World War I, who needed easier access to an accurate timepiece than could be had from a pocket watch. Bulova's wrist-mounted option caught on, and veterans brought the idea home from the battlefield.

Over the years, Bulova has had other firsts that go beyond watch making. In 1941, the company made advertising history when a commercial for its wares aired during a baseball game. Legend has it the company paid a whopping $9 for the commercial (for more on Bulova's commercial first, see our article 10 TV Moments that Changed the World). And the company's Accutron quartz-tuning-fork–regulated technology, which has been used everywhere from NASA satellites to the first moon walk to Air Force One, remains a solid contender in the watch market today.