Time Zone Information
People used to think the
whole world should set their clocks to the same time. This
was a problem, though, because the sun doesn’t shine
on all parts of the world at the same time. For example, if
every clock in the world was showing 3 p.m.— in some
places of the world the sun would be rising, other places
it would be setting, and still other places would be completely
in the dark.
In 1884 scientists solved
this problem by dividing the world into 24 time zones. Each
zone is approximately 15 degrees longitude
wide; equal to about 1,035 miles wide. Greenwich, England
was chosen to be the location for universal time because it
is located along the prime meridian.
The time in each time
zone is calculated by this universal time also known as Greenwich
Mean Time (GMT). For example, Chicago, is GMT minus 6
hours. When it is 7 p.m. in Greenwich, it is 1 p.m. in Chicago
(7-6 =1). (note: this changes and hour when the US switches
between daylight savings
time)