1. Describe how each of these calendar types work:
(1) Solar
 365.25 day year based on Earth’s rotation around the sun

From vernal equinox to the next=Tropical year or Astronomical year
(2) Lunar
 29.5 day calendar based on the moon’s cycle & phases

Month is from new moon to new moon

Lunar year is 354.5 days
(3) Lunisolar

Mutual relations between solar & lunar calendar

Joint action between the two & an attempt to keep both aligned

Especially important for tracking the seasons
2. From our study of calendars, list and describe some of the ways that calendars have been used throughout history.

Both to record & plan for

Agriculture-planting season (seasons)

Food-migrations/when animals can be caught

Religious events

Record major social event/wars/significant events to plan for
3. What have been some of the biggest challenges in creating accurate calendars?
 Earth’s 23.5 degree tilt

Tools to measure accurately the orbit around the sun

Differences in what was important to add to a calendar

What references to use-consistency in using
 Moon’s orbit of 29.5 days does not match earth/sun
4. Today, which of the main calendar systems is most widely used? Explain why

Gregorian (Christian)
Why? Influences on modern world by mostly Christian Europe, historically European influence from 16 th century on
*Julian calendar still used but in limited scope

5. Today, what is used as the reference point we use for organizing history? How does this system work?

Birth of Christ year 1

No zero year
 System devised in 525 AD but not widely used until the 800’s
* Civil years begin on Jan. 1 st
5a. Spell out and describe the following acronyms:
AD: Anno domini “In the year of our Lord”
BC: Before Christ
CE: Common Era or Christian Era
BCE: Before Common Era or Before Christian Era
Keeping Time Today
6. How many world time zones are there? 24
6a. Describe the 2 methods we use to tell time

12 hour day-Midnight to noon (AM). Noon to midnight (PM).

24 hour day-Midnight 0:00/24:00 noon=12:00 6pm=18:00
7. How many world time zones are there? 24
7a. How are longitude lines used to organize them?

Every 15 degrees longitude

360 degrees/24 hours=15 degrees

Follows sun so sunrise/sunset at correct times
7b. Why are thy crooked on the map/globe?

To avoid splitting countries, states, etc.
8. Which line is used as the reference point for time? (name and degree #)

Prime Meridian

0 degrees longitude
8a. Where is this line located and why do we use it?

Runs through Greenwich, United Kingdom

Royal observatory there can measure location (so a reference)

GMT: Greenwich Mean Time (traditional)

UTC: Coordinated Universal Time (newer)
9. Which line is used as a reference point for the starting of a new day? Explain how the process works.


International Dateline (180 degrees, East and West)

Crooked on a globe/map to adjust for countries (see 7b)
10. In addition to tracking time with months and days, we also divide our year into
“seasons”, based on the sun’s direct rays. List the seasons and answer the following for each.
a. On what day does the season begin?

Spring-March 20 th (2014)

Summer-June 21 st (2014)

Fall-September 23 rd (2014)

Winter-December 21 st (2014)
b. What is this event called?

Vernal equinox=spring

Summer solstice=summer

Autumnal equinox=fall

Winter solstice=winter