(attribution and license for the above image can be found at http://en.wikipedia.org/wiki/File:DW-5600E.png)
Watches are handy devices for working or working out. They tell time to varying degrees of accuracy, with two major types, mechanical and quartz watches. There are quite a few comparisons between them. Most mechanical watches are accurate to about 3 seconds a day, whereas quartz watches are accurate to about 15 seconds per month.
High-end mechanical watches are mainly sold as jewelery, being built out of expensive materials (like gold or platinum), and receiving extensive finishing treatments on almost all of it's components. Mechanical watches are viewed as superior only in the highly accomplished artisan/craftsmen sense, building intricate machinery that takes years to master and produce. They almost never achieve accuracies of standard quartz watches. While they do not require a battery, they do require regular service intervals, since there are critical parts in the watch that are subject to wear. There is a series of articles that describes how various watch companies are viewed from the very high-end perspective. Lots of admiration for hand-made watches as works of art (A. Lange & Sohne, Nomos, or Patek Philippe), and not so much for assembly-line watch manufacturers (Swatch, Breitling, Omega,...) Views support of hand-crafted watches as being the same as supporting artists in their craft.
Quartz watches are accurate, and have several ways of enhancing their accuracy further. Thermal compensation of the watch can make a watch accurate to 5-20 seconds per year, a huge improvement over standard quartz watches, (which are typically accurate to about 15 seconds per month). The Seiko 9F quartz movement, used in the Grand Seiko line of watches, is rated +/- 10 seconds per year, and this article describes it nicely (although it lacks technical details).
Another popular method is to synchronize the watch with a time signal from an atomic clock on a daily basis, and many Casio G-Shocks employ this method. The advantage of synchronizing with an atomic clock is that you can be sure that your watch is accurate to the second as long as the time syncing procedure was successful. The disadvantage is that you have to be near to an atomic clock broadcasting tower to receive the signal.
Many people enjoy dive watches, because of their high rated water resistance and their no non-sense design. There are two standards that govern water resistance ratings, ISO 2281 and ISO 6425. ISO 2281 is used for most G-Shocks, (the Frogman is the exception), and samples a few watches out of a lot in order to verify that the water resistance rating holds. ISO 6425 is the diver's standard, and is guaranteed to be water resistant, since every single watch that is rated ISO 6425 has been tested. One thing to remember is that even though a watch has been fully tested, 5-10 years can wreck havoc on a watch's gaskets and seals, so even ISO 6425 testing cannot guarantee water resistance 100% of the time.
A good article to read is "Telling Time Underwater", by Nicholas Hacko, who has seen first-hand the bad effects of careless watch use. The gist is that it is better to wear a cheap G-Shock while doing water sports, than it is to wear a $5,000 diver watch while diving.
GPS Watches use the global positioning system in order to record data for jogging/biking/hiking. There are some good choices like Garmin 620, Garmin Fenix 2, or the Suunto Ambit 2. They do a great job as a training device, but because of the high power draws of the gps tracking system, you will receive around 10 hours of usage time before it has to be recharged. Both the Garmin and the Nike+ use a computer and software to interface with the watch, to download data, and to set watch display preferences.
Favorites
I prefer watches that are as maintenance free as possible. Some features that are worth having are a perpetual calendar (no adjusting the date at the beginning of the month), solar powered (less frequent battery changes), automatic time syncing (no adjusting the time because the watch is inaccurate), shock resistance (dropping a watch accidentally should not affect it's accuracy), and water resistance (don't let a splash of water destroy your watch).
My current favorites are:
(1) G-Shock GW-5000, a classic digital watch, with a steel case and case-back.
(2) G-Shock GXW-56E-1JF, a digital with enhanced shock absorption capabilities.
(3) G-Shock GXW-56-1BJF - a much more readable version of the GXW-56E.
- Casio G-Shock GXW-56E-1JF (1 minute) - current watch that I own.
- Casio G-Shock GW-5000-1JF (2.5 minutes) - a model with an all-metal case, and a screw-down case-back, and soft resin. The great thing about the watch is it's substantial weight. The bad things are that the resin band doesn't seem to be as sturdy, the atomic time synchronizing feature doesn't work where I live, and the time isn't displayed in all modes (a nice feature to have when using the stopwatch or the countdown timer).
G-Shock Tough Test (3 minutes) - Drop test, hammer test, piston test, vibration test, low temperature ice test, deep water pressure test. A comprehensive GX-56 specific torture test description, toughness that you can't get with mechanical watches.
Vintage G-Shock DW-5600C (44 minutes) - A nice retrospective of 1987 and the DW-5600C.
Watch out for Fakes! - Don't buy a fake g-shock!
History of Casio's Animated Running Man watch collection - a fun retrospective on older jogging watches. Here's an example of a running man watch that can display the time in stopwatch mode.
CX Swiss Military Watch Tests - a video of some torture tests of a 6,000 meter water resistant watch, even tougher than a g-shock. A beast of a watch.
Watch Case Materials Explained: Titanium -
nice definitions for durability, strength, and toughness. Titanium is half
the weight for the same volume, as steel. And better at corrosion resistance, but scratches easier than steel.An Electrical Engineering View of a Mechanical Watch (53 minutes) - an MIT lecture which explores how a mechanical watch works.
Time is money - A nice introduction to Swiss watchmakers and the watch industry.
What's in Your Watch? - A short article about Tag Heuer's $4,000 (list price) watches, with assembly-line movement with plastic components. What exactly are you paying for?
GPS Modernization - Plans to upgrade the global positioning system.
What is NTP - Computers need to have their internal clocks synchronized, and the network time protocol (ntp) uses the internet to synchronize the local clock with an internet time server.
Chip-Scale Atomic Clock - uses cesium 133 atoms and a laser to produce a clock that's a million times more accurate than quartz, but uses 115 milliwatts (still too much power to be used in a watch). See also a "cold" rubidium atomic clock, that could be up to 1000 times more accurate than the chip-scale atomic clock.
Introduction to Atomic Time Frequency Standards 2011 - A terrific introduction to atomic time keeping, which explains how to measure time.
Source From: https://sites.google.com