[IAEP] GPA Notes 7/23/09

[Edward Cherlin]

On Thu, Jul 23, 2009 at 6:38 PM, Anurag Goel<agoel23 at gmail.com> wrote:
> GPA Notes 7/23/09
>
> Who: Walter, Caroline, Jennifer, Anurag
>
> 10:45: Set-up computers and projector. Walter worked on Clock program in
> Turtle Art
>
> Walter: Today we are going to use the turtle to play with clocks. (Walter
> shows the kids the clock program he made in Turtle Art. The kids compare
> Walter's clock with the other clocks in the room.
>
> Walter: Why do we use 12 numbers on the clock instead of 10 or 6 or 5?

And why is the beginning hour of the day 12 and not 0 or 1?

Because Leonardo of Pisa (Fibonacci) found out about Arabic numerals
and published his book, Liber Abaci, during the Crusades. The Catholic
Church took the position that the (Hindu/)Arabic 0 was an infidel
invention, counter to the essential doctrines of Christianity. That
is, that nothingness is irreligious when religion is founded on
Creation. At that time clocks only existed in monasteries and
cathedrals. Household clocks and pocket watches stayed with Roman
numerals, and we are still stuck with this prejudice in the US. The
situation is different in the sciences, in the US military, and in
almost all other countries. All of them use a 24-hour clock that runs
from 0:00:00 to 23:59:59 every day.

This also gets rid of the ambiguity about 12 AM and 12 PM, and the
resulting need to say 12 noon or 12 midnight. And the other ambiguity
about 12 midnight--Which day is it? 0:00 is clearly part of the day
that follows it.

Clock time is the canonical example of a ring in mathematics, where
you have addition, subtraction, and multiplication, but not division.
-- 
Silent Thunder (默雷/धर्ममेघशब्दगर्ज/دھرممیگھشبدگر ج) is my name
And Children are my nation.
The Cosmos is my dwelling place, The Truth my destination.
http://earthtreasury.org/worknet (Edward Mokurai Cherlin)