The Division of Time - Which Level of Accuracy ? Time is divided naturally by striking astronomical phenomena such as the periodical renewal of the seasons, the phases of the moon, or the regular succession of day and night.
To divide time into smaller fractions, artificial means are needed, such as sun dials which mark the movement of the shadow cast by the sun; or clepsydras which use a controlled flow of water. Since 1657, the oscillatory movements of a mechanical movement have been used to divide time.
The electronic age did not pass watches by. In the late 1960s, a Swiss research group designed and tested the first electronic watch movement, which later became known as the quartz movement. These battery-powered watches also permitted a deviation from the centuries-old analog display with the introduction of digital display.
Quartz watches are extremely accurate thanks to their high frequency of vibrations (32 kHz). Their daily variation is equivalent to much less than a second per day.
Comparatively speaking, the frequencies of oscillations (number of one-way movements of the regulating organ per hour) mainly used in mechanical watches range from 21,600 Ah (3 Hz) to 28,800 Ah (4Hz), allowing a variation of less than 10 seconds a day.
It says Water Resistant, but can I swim with it ? Water resistance is measured in bars (unit of pression, 1 bar being equivalent to 1 atmosphere), and watches are tested at these pressures for certain period of time. Exceptional pressure, as when diving, may exceed those limits, so if you are a keen diver you will need a watch that can tolerate that pouding.
Manufacturers often measure water resistance to a number of feet (ft), meters (m) or atmospheres (atm). Watches marked "water resistant" with or without additional indication of high pressure must comply with NIHS 92-10 watch Standard (corresponding to ISO 2281 international Standard). Such watches are designed for everyday life and must be water resistant during exercises such as short swimming. They can be worn in different temperature and pressure conditions but are under no circumstances designed for scuba diving.
Divers' watches must be water resistant at 330 ft minimum. They must also feature a time controller and comply with standards provided by NIHS 92-11 (ISO 6425) : luminosity, shock resistance, anti-magnetism, band solidity.
Remember that if you are going to be mountain climbing, parachuting, sky diving, hang gliding, or skiing, you will need a watch that is atm damage-protected as pressures change both above and below sea level.
For regular water use, solid metal cases or specially constructed products are recommended, including screwed-in case backs and crowns.
Remember that only professional changing battery will guarantee the seals and thus the water resistance of your timepiece.
What Maintenance will the Watch need ? Mechanical and automatic watches should be cleaned and serviced every three years to ensure trouble-free time keeping. The moving parts of quartz watches also need maintenance, as they are not under tension and any small, foreign particle is sufficient stop them.
Where fitted, the battery needs to be changed when drained. This is the time for routine maintenance. Apart from changing the battery, digital quartz watch need no routine maintenance. Where water resistant seals are fitted, cleaning is required less often, however seals must be changed whenever the case back is removed. Otherwise they should be changed annually and resistance checked using pressure equipment, through the manufacturers' agent.
It is worthwhile remembering that regular exposure to chemicals, or sea water, can damage straps, plated cases and bracelets and a solid metal or specially constructed material is recommended if regularly used in these conditions. Cosmetics and perfumes can also cause damage if directly applied to plated dials and straps.
What is the difference between a Chronograph and a Chronometer ?
What does "Complication" mean ? A Chronograph is a timepiece equipped with additional time measurement functions independent of normal time-telling.
A Chronometer is a high-precision timepiece which movement, after rigorous testing, has received an official timing certificate from and official timing bureau.
Watches providing additional measurement functions to the hours, minutes and seconds are referred to as "Complications". The best-known complication watches are calendar watch, the most common of which display only the date. There are also chronographs with a center seconds hand which can be started, stopped and brought back to zero using one or two push-button on the side of the watch. Other additional functions include second time zone, alarm, moon phase, repeater, perpetual calendar, etc.
How long is the Lifetime of a Watch Battery ? Usually between two and five years, depending on the type of the watch, its dimensions and the quantity of energy requested by the different functions. For instance, a chronograph will have a higher energy consumption than a watch indicating the hours and the minutes only.
Certain types of watches feature a power reserve indicator : when the seconds hand starts jumping every five seconds, it is time to have the battery replaced by a qualified watchmaker. Special lithium-iodine batteries reach a theoretical lifetime of ten years.
What is a Unidirectional Bezel ?  Often the bezel (top ring on the case), serves to record additional data, and can often move in both directions to provide a number of functions. A unidirectional bezel only turns one way to prevent any danger of false man oeuvre. Especially important when being used to measure diving times as even if the bezel is knocked and moved it will simply indicate the diver has less air or decompression time rather than more.
"T Swiss Made T" or "Swiss T 25" : What does it mean ? In order for timepieces to be read in the dark, a radio luminescent material is laid on the dial indexes and hands.
According to ISO 3157 Standard, only the use of the following radio nuclides is authorized for timepieces: tritium (3H) and promethium (147Pm). It is important to specify that these radio nuclides emit a radiation of low energy, perfectly confined by the watch case and glass; they may under no circumstances threaten the health of the watch user.
ISO 3157 Standard allows an optional marking for timepieces emitting less than a certain value. The marking may be made on the dial as follows:
deposits activated by tritium : T
deposits activated by promethium : Pm
On the other hand, timepieces with a higher value, such as divers' watches, must be marked as follows:
deposits activated by tritium : T 25
deposits activated by promethium : Pm 0,5
The indication "T Swiss made T" means that the watch is Swiss and contains a certain quantity of tritium that emits less than 227 MBq (7,5 mCi). The indication "Swiss T 25" means that the watch is Swiss and contains a certain quantity of tritium that emits less than 925 MBq (25 mCi).
What are the Jewels in the Context of Watch Movements ?  The jewels are synthetic sapphires or rubies which have been drilled, chamfered and polished to serve as bearings for gears in watches, reducing friction or mechanical parts to a bare minimum.
Generally speaking, on may say that a simple mechanical watch (hours, minutes and seconds hands) should include at least fifteen jewels located in the places most subject to wear due to friction. It should be fitted with a shock-absorbing system on the balance, a good quality balance-spring and an unbreakable spring.
Why is this Watch so much more expensive than that one ? A good watch is first of all one which is appealing.
Generally, mechanical watches, by nature of their movements, are more costly than quartz watches. Beyond this, there are a number of factors that affect the cost of watches.
In relation to the movement, one may say that even on cheap models, this part is well designed and that all the highly functional elements make use of the latest technologies discoveries; economies are made on the non-functional parts. In very carefully made movements, all parts, whether functional or not, are finished with great care. All steel components are polished; bridges are decorated and chamfered; all parts are of the highest quality and undergo stringent tests; in short, the manufacturing standards are extremely high.
Case materials vary. There are plastic, resins, stainless steel, base metal (usually brass), gold-plated base metals, gold-filled and precious metals. Check either the back of the watch case, or the documents accompanying the watch for the disclosure of metallic content. Plastic and resin composites generally are the least costly and are found primarily in fashion and sport watches. Stainless steel is not a precious metal and is widely used in sport watches.
Prices of gold-plated watches vary depending upon the karat age of the gold (e.g. 14 kt or 18 kt) and the thickness of the plating - measured in microns. Gold plating can range from 2-micron thickness to 30 microns and more. Precious metals used on watch cases include varying karat gold, sterling silver and, in some very high-end watches, platinum.
Crystal types also vary, but with fewer options. Generally, the crystal, which is the glass-like covering designed to protect the dial of the watch, is either plastic, mineral glass, or synthetic sapphire. Plastic is mostly used in lower-priced, mass-market watches. Mineral glass is more common and sturdier. Sapphire crystals, more expensive than mineral glass, are not only sturdy, but also highly scratch-resistant.
Bracelets can also influence watch prices considerably. Aside from plastic and rubber strap, leather and metal straps can dramatically affect the cost of the watch. Leather straps can range from $10 to $ 100 for specially treated or exotic (though not endangered) skins. Similarly, metal bracelets can range from inexpensive base metals to precious metals, to specially developed tungsten carbide or titanium.
Today, the highly competitive market is such that the quality of watches is inexorably pushed upward, a trend which translates into a range of products constantly improved in order better to meet consumers' need and expectations. |
