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From: Young, Derrick (no email)
Date: Mon Oct 18 2004 - 16:31:19 EDT
Gary,
I started to dismiss your question as being frivolous - but it is not - as I
was reminded by my son's third grade class. I went in and talked for about
an hour on navigation, maps and charts, scales and time. I also brought
along a globe, sextant, compass, a couple of charts and other things so that
they could see what I was talking about.
Interesting thing is that one of the students asked that question - is 12
noon morning or afternoon? From a mathematical point of view, sounds like
the same question as asking if zero is positive or negative. In math, you
carry the sign from the direction that you are approaching - but in time
discussions, this is meaningless fluff.
There are several different cultural definitions for when one day starts and
another ends. They include dawn to dawn, dusk to dusk, or as we have
adopted, 00:00:00 to 23:59:00. Using this cultural bias, midnight is
considered to be the start of the day - I don't really want to get into the
merits of other cultural clocks and calendars here). If we accept this
definition (midnight being the start of the day) we could correctly write
the time as 00:00:00, 00:00:00 AM (redundant) or if you are using a 12 hour
clock, as 12:00:00 or 12:00:00 AM (again, redundant).
Now to the next part of the question - what about noon.
Dividing the day into two equal portions was done long before Eratosthenes
and his accurate measurement of the circumference of the earth. We have
carried this same concept forward even though we now start our day at an
arbitrary time (midnight), based on an arbitrary location (local time
meridian).
If the morning and evening portions of the day are equal (both 12 hours) and
we start the morning at 00:00:00 (I have a hard time putting in the colons!
Want to write this as 000000!), then the afternoon (or more correctly
evening) portion of the day starts at 12:00:00, or on a 12 hour clock
12:00:00 PM.
What you should come away from this is that this really depends on your
cultural definition as to when the day starts. In my family, midnight was
always the end of the day and noon was neither morning or afternoon. It was
not until I started learning something about navigation that I realized that
was not always the case.
Don't know that I answered your question - may have just thrown more fuel on
a smoldering fire.
Enjoy,
derrick
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