Glossary R-Z

TACHOMETER	instrument for measuring speed over a measured distance. A racing car covers 1 mile in 30 seconds. The sweep second hand, when stopped at the end of the mile, would point to the 120 on the tachometer. The average speed in 120mph. Counts the number of rotations to see how fast you travel over a measured distance.
TANTULUM	a grey, heavy, and very hard metal. Tantalum is used to make avariety of alloys at high melting point and high strength. Tantalum is completely immune to body liquids and is a non-irrititating material.
TELEMETER	stopwatch or chronograph function with a scale that measures the distance of something from the wearer of the watch through the amount of time it takes for sound to travel.
TOURBILLON	eliminates errors of rate due to earth’s gravity of vertical positions. “whirlwind” a complex mechanism requiring the highest watch making skills: consists of a mobile carriage carrying all the parts of the escapement. It is a regulating device which connects for the gravity-caused differences in run time in a mechanical watch. (Shifts of weight)
TIME ZONE	the world is divided into 24 time zones spaced at intervals of 15 degrees in longitude. The zones start at 0 with Greenwich. Within each time zone, the hour and minute of the day is defined to be the same. Time zones are usually specified by the number of hours they differ from GMT. EST is GMT 5 hours.
TITANIUM	a metal, gray in color, that is used for watch cases and bracelets. Much stronger and lighter than stainless steel and hypo-allergenic. It is 30% stronger and 50% lighter than steel. It is very resistant to salt water corrosion makes it useful in divers watches although since it can be scratched easily some manufacturers use a coating to resist scratching.
TRAIN	the series of wheels in a watch: center wheel, third wheel, fourth wheel, and escape wheel.
TRIBOLOGY	the study of the interaction of sliding surfaces.
TRIMMER	found in expensive quartz movements it is a variable capacitor that changes the frequency of the oscillator in order to advance or retard the rate of the watch.
TRIPLE DATE CALENDAR	complication that provides month, day and date.
TRITIUM	a slightly radioactive substance that collects light and is used to allow the hands or hour markers to glow in the dark. The radiation is so low that there is no health risk. Watches with tritium must be marked with the letter T on the dial near the 6’oclock.
TROPIC OF CANCER	located 23.5 degrees north of the equator. On June 21st, the sun is directly overhead the tropic of cancer at noon. This is the beginning of summer in the northern hemisphere and the beginning of winter in the southern hemisphere.
TROPIC OF CAPRICORN	located 23.5 degrees south of the equator. On December 21st the sun is directly overhead of the tropic of Capricorn at noon. This is the beginning of winter in the northern hemisphere and the beginning of summer in the southern hemisphere.
UNI-DIRECTIONAL BEZEL	a bezel that rotates clockwise and counter clockwise.
VHP	very high precision is a quartz movement with a temperature sensor to keep variations within extremely narrow margins. The movement corrects itself to precision +/- 10 seconds per year.
VIBRATION	movement of a pendulum limited by 2 extreme positions. The balance of a mechanical watch generally makes 5 or 6 vibrations per second (18,000-21,600 per hour.) A high frequency watch makes 8-10 vibrations per second (25,200 28,800 36000 per hour) The higher the number the smoother and more accurately the watch will run.
WATERPROOF	no watch is 100% waterproof.
WATER RESISTANT	water resistance is reduced by age, wear, extreme temperatures and high pressure. Water resistance is measured 4 ways where 1ATM= 1 BAR = 10m = 33.3ft In order to maintain stated water resistance the gaskets that seal out water must be checked and replaced regularly.  3 ATM or 3 BAR (30m or 100ft) can withstand gentle splash such as rain 5ATM or 5 BAR (50 or 165ft) suitable for showering or light moisture 10ATM or 10 BAR (100m or 330ft) swimming or snorkeling 15ATM or 15BAR (150m or 500ft) suitable swimming, snorkeling and low diving 20ATM or 20BAR (200m or 660ft) suitable for swimming, diving and high board diving 30ATM or 30BAR (300m or 990ft) suitable for swimming, diving and high board diving 100ATM or 100BAR (1000m or3300ft) suitable for deep sea diving
WHITE ON	analog watch that is able to display functions at the touch of a button. An easily legible white numeric display appears on the inside surface of the crystal when any digital function is activated.
WHEEL	pinion circular part revolving an axis to transmit power or motion. Center wheel, front wheel, hour wheel, minute wheel, third wheel, transmission wheel.
WORLD TIME WATCH	24 different time zones that can display the current time in any part of the world.
WRIST COMPUTER	a watch that can directly interact with a computer.
YACHT TIMER	a countdown timer that sounds warning signals during the countdown to a boat race.