Gravitational field intensity

Gravitational field intensity (gravitational field strength) is the amount of force applied on each unit of mass of an object at a point in space. "Space" includes a region on or near the surface of a planet.

This means that the gravitational field strength, g is equal to the force experienced by a mass of 1kg in that gravitational field.

acceleration due to gravity

The acceleration due to gravity is the acceleration of a body due to the influence of the pull of gravity alone, usually denoted by 'g'. This value varies from one celestial body to another. For example, the acceleration due to gravity would be different on the Moon as compared to the one here on Earth. Similarly, you would have different values for both Jupiter and Pluto.

Galileo theorized that in the absence of air, all things would truly fall with the same acceleration. 300 years later the crew of Apollo-15 demonstrated this on the Moon (which has gravity but lacks air) by dropping a hammer and a feather.

An atomic watch is handy because it automatically adjusts for Daylight Saving Time (DST), often mispronounced as Daylight Savings Time, leap years and even leap seconds. It contains an internal antenna and program that is set to search once a day for the 60 kHz radio signal emitted from the WWVB transmitter in Ft. Collins. When it finds the signal it decodes the time then sets itself. The Ft. Collins transmitter has a radius of 1,864 miles (3,000 km), making it available to the most of the United States with the exception of Hawaii and Alaska.

If you travel overseas with an atomic watch, it will continue to function as a quartz watch but will not receive radio controlled updates. Although Europe has its own atomic clocks, the transmitter frequency used in Europe differs from the one used in the United States.

(WWVB is a NIST time signal radio station near Fort Collins, Colorado, co-located with WWV. WWVB is the station that radio-controlled clocks throughout North America use to synchronize themselves.)

Electric watch, which commonly means any watch that is powered by electricity, in horology has become a generic term for the first generation of electrically powered watches which appeared starting in 1957, before the invention of quartz watches in the 1970s. Their timekeeping element was either a traditional balance wheel or a tuning fork, driven electromagnetically by a solenoid powered by a battery