running events in the Olympics have been timed in hundredths
of seconds because of electronic timing devices.
The United States
is the only developed country that does not
use the metric system for its principal units of measurement.
Almost all scientific
measurements are made using metric units. The
metric system is based on the decimal system (units of
10) and follows a consistent naming scheme using prefixes.
The US National Aeronautics and Space Administration
(NASA) spent $125 million on
a spacecraft that flew 416 million miles over
9 1/2 months before crashing on Mars. The spacecraft crashed
due to a contractors error in converting pounds
of force into another unit of force called
newtons. One newton is the amount of force required
to accelerate 1 kilogram of mass 1 meter per second each
Many cars and
trucks require metric tools for
(1 cm2 ) is about the size of your little fingernail.
The mass of one
cubic centimeter (1 cm3) of water
at standard temperature and pressure is 1 gram.
The US Conventional System of Measurement
is a modified version of the
British Imperial System, which is no longer
As of January 1, 2000, it is a
criminal offense in Great Britain to sell most
packaged and loose products using
imperial measures (inches, pounds, and so on).
One exception is precious metals.
One of the few British Imperial units of
measure that remains in world-wide use is the barrel,
primarily for oil.