The Unit of Time
The second (sor sec)is the standard
unit in both the metric and English systems. Instead of the unit 10, multiple
units of the second are based on the number 60 and are from the Babylonians.
The Bayblonians were the first to divide the day into 24 hours and a week
into 7 days. 60 seconds equals 1 minute and 60 minutes equals 1 hour.
A second is 1/86,400 (60 seconds * 60 minutes * 24
hours = 86,400 seconds) of a solar day. A solar day is the time it
takes the sun to go between two given points. The standard unit, the second, is divided by 10 into .1 (tenths) of a second, .01 (hundredths) of a second, and .001 (thousandths )of a second (also called a milisecond.)
Earth Meridians
Your globe is marked with 12 meridians extending from
the North Pole to the South Pole. If the sun is directly overhead one of
these meridian lines on your globe, it means it would be noon in all the
places on that meridian. The earth is always revolving so two hours later
the sun would be directly over all of the places on the next meridian line.
How Time is Measured
The earth is divided into 24 time zones, each of which
is centered on a meridian line. Meridian are sometimes called "hour lines"because the earth turns 15 degrees in one hour.
See the table below for current times around the world.
Click here to see a map of time zones around the world.
Return to Main Page