4
RADIO-CONTROLLED TIME*
A radio-controlled time device is often confused with an atomic clock.
However, a radio-controlled time device receives its time information
from the atomic clock each day through an internal antenna. The
radio- controlled time device searches for an exact time signal every
night when the signal from the WWVB is the strongest. The signal can
be received up to 2,000 miles away through a radio-controlled time
device.
LCD
“LCD” is an acronym for ”Liquid Crystal Display”. This is a common
type of display screen used in televisions, computers, watches, and
digital clocks.
BAROMETER & BAROMETRIC PRESSURE
A barometer is a device that measures the pressure of the air pushing
on it—this measurement is called the barometric pressure. We don’t
actually feel the barometric pressure because the air pressure is
pushing equally in every direction.
RELATIVE AIR PRESSURE
Relative air pressure is the same as the barometric pressure. The
calculation of relative air pressure is a combination of the absolute air
pressure and the altitude.
ABSOLUTE AIR PRESSURE
Absolute air pressure is the actual air pressure on the barometer
without regard to altitude.
INCHES OF MERCURY (inHg)
Inches of Mercury is the common unit of measurement for air pressure
in the United States.
HECTOPASCALS (hPa)
Hectopascals are the common units of measurement for air pressure
in the International System (SI) of measurement. The hectopascal
holds the same value