Clock Watching...

The title was inspired from Jason Mraz's Song...But actually this post has nothing to do with Mr. A-Z...

Let's get to the topic..

Have you ever thought about a clock numbers? well, just now I was thinking about why does a clock has 12 numbers. here is what I found...

"The planet Earth is 24,000 miles around (circumference) and spins at 1,000 miles per hour, so a day is 24 hours long (24,000 miles divided by 1,000miles/hour = 24 hours). Since roughly half of that time is daytime, we have our clocks with 12 hour faces. There are plenty of clocks with 24 hour faces, but most still have twelve, correctly assuming that people will be smart enough to tell daytime from nightime.

Navy and submarine clocks have two numbers rings on one face - the outer ring of numbers (1-12) is for AM, and the inner ring (13-24) is for PM."
source: http://answers.yahoo.com/question/index?qid=20081203035902AA8IyN8

Then, I found other question, what are am and pm stand for?

AM stands for ante meridiem which means "before mid day" or "before noon"
and
PM stands for post meridiem "after mid day" or "after noon"
Source: http://en.wikipedia.org/wiki/12-hour_clock

I just want to share what I researched...I hope you can learn something from my post..