Question I
Paleolithic people are sometimes thought of as having made indications on stones and bones of the phases of the moon. How many ways can you think of that you might indiate in some form of writing the phases of the moon and their duration?
Question II
Calendars keep track of time - usually those periods we call "days", "months" and "years". Shorter time periods that we call "hours" "minutes" and "seconds" are handled in other ways.
Some calendars operate on moon cycles, other on sun cycles. Lunar calendars work in "months" which are rooted in the time it takes for he moon to go through its phases.
How long is a mood cycle? That depends on what constitutes a lunar cycle. Two kinds of months are defined:
a. Types of "months". Synodic (full moon to full moon; or new moon to new moon 29d12h44m2.8s)
b. Sidereal month: one revolution around earth with respect to the stars. (27d7h43m11.5s)
Point to ponder!
Why is one longer than the other?
Since the length of these moon cycles are different the number of cycles in a year (defined as one journey around the sun) is also different.
c: 12.38 synodic months in a year 365.25/29.5
d: 13.38 sidereal months in a year 365.25/27.3
Point to Ponder!
What happens when you try to have an even number of months in a year?
Suppose you just started a new year after a fixed number of moon cycles. What would happen?
PROJECT
So! Try to construct a calendar that integrates the moon cycles and the year!
For answers to these problems click here.