Introduction

We track our existence through days and years. Our age is how many years have passed since our birth. The school semester consists of 66 class days and four final exam days. These are connected to the rising and setting of the Sun together with its changes in sky path through the seasons, but why are there 12 months with irregular numbers of days in each and 365 or 366 days in a calendar year? In this module, we will learn about both the history of our calendar and some alternate ways of counting time to prepare us for the diverse ways in which native American cultures tracked time before contact with Europeans and European-Americans.  This will lead us to a way to track objects in the sky relative to the stars and prepare us for studying planets.

Module Objectives

1. You will be able to explain how ratios of days and remainders from division relate Sun and Moon cycles to the calendar.
2. You will be able to describe the evolution of the modern Gregorian calendar from the Roman calendar.
3. You will be able to find the number of days between two dates in the calendar.
4. You will be able to use the equatorial coordinate system for tracking sky object positions based on the stars.

Module Structure

• Readings
  • Textbook Sections
    • 4.1 Earth and Sky
    • 4.4 The Calendar 
  • Online Resources
    • Sirius: The Brightest Diamond in the Sky
    • 2.4 The Main Types of Lunar Calendars
• Reading Check
  • Check Your Calendars Reading
• Activities
  • Build Calendars Pages in Your Star Group
  • Discuss Your Calendar with the Class
  • Discuss Calendars with Your Greek Letter Group
  • Make Observations of the Sky for the Calendars Module
• Learning Check
  • Check Your Calendars Module Learning
• Reflection
  • Reflect on Calendars Module Time