The Modern Watches and Precise Clocks

In the evolution of watch and clock making, mechanical clocks became the foundation upon which other types of watches and clocks were made. The theory that a mechanical mechanism could "tick" of time in specific, set increments is the basis of both the quartz watch and the atomic clock.
The Quartz Watch
The Americans, Swiss and Japanese all played a part in the invention of the quartz watch. One of the first quartz watches ever built for mass market distribution was made by the Sinclair Company. It had the right idea, using quartz crystals to complete an electrical circuit that would move a mechanical movement in precise increments, but the outer casing and primitive use of the quartz proved disastrous.
Sinclair's "Black Watch" was a digital model quartz watch that was introduced in 1975. It had all kinds of problems from losing or gaining time during the changes in hot and cold weather to creating static that would affect its time keeping abilities simply by walking on nylon carpet or having static due to clothing or air conditioning. In addition, it had a battery that could only hold a charge for 10 days. There appeared to be as many returns of this watch as there were sales!
The quartz watch was still a desirable option to explore and many other companies had models of digital quartz watches in the experimental stages and ready to sell. However, the reliable early quartz watches were still about $125 or more -- very expensive for the mid-1970s. These newer, more expensive watches were at least able to keep good time. In fact all well-made quartz watches kept very accurate time and in 1976 Texas Instruments introduced a model at the Chicago Consumer Electronic Show that could be produced in mass quantities for a mere $20.
The makings of a quartz watch started with the first watch battery in 1954. Next came the development of the integrated circuit in 1959. With light-emitting diodes (LED)being developed around 1962, all of the elements were in place for a digital quartz watch. In fact, the very first prototype, the Beta 21, came out in 1967. The development of liquid crystal displays (LCD) in 1968 gave digital watches the look they have today. Pulsar is credited with creating the first digital watch in 1970.
The Atomic Clock
Universal time is measured by an atomic clock which runs by using the element, cesium, to keep it going. Just one gram of cesium is enough of a "fuel" to run an atomic clock for one year. Cesium is found in granite and the one gram supply can be extracted from a piece of granite that is about a cubic foot in size.
This silvery metal is in liquid form at room temperature and is considered the most electropositive and alkaline element in the periodic table. It is used as a catalyst in photoelectric cells to react with hydrogen and create the necessary movement of the atoms which create a microwave frequency and natural resonance to define a single second. This cycle used to measure a second is actually made up of exactly 9,192,631,770 oscillations of the cesium atom's resonant frequency.
Of course the atomic clock is not the type of clock one keeps in their home, but it is the national standard for keeping time in America. For home use, today's quartz clocks and watches offer a highly precise way of keeping time.