Calendar for a Planet
Objectives : to explore various ways of factoring multiples and to establish a time-keeping system for an imaginary planet, to discover a universal among cultures (the measurement of time by astronomical events), and to create a multicultural calendar for an imaginary planet.
Part I
Materials: Information about Mesoamerican : Aztec , Mayan , and other Native American calendars, Jewish , Chinese , and Islam's calendars , butcher paper or chalkboard, writing instruments. For each culture find out how long the year is, when they began counting the years, and how the year is divided (months, weeks, days).
1. Compare calendars and make two lists. One list of the things that are different about the calendars, and another of the things that are the same.
2. Presents lists.
3. Discuss lists.
Discussion Questions:
What is the significance of the numbers 365 and 29?
In what ways is life connected to the movements of the Moon around the Earth, and the Earth around the Sun? How do these movements influence how we live?
Part II
(toca aqui para una traducción en español de esta parte)
Calendars were invented as a way of measuring time. Time is measured by events which occur at regular intervals. One of those events is the rotation of the Earth. The Earth rotates once every 24 hours.The hour was invented as a way of dividing the time in one day. One day is equal to the time it takes the earth to make one rotation. Another way we measure time is by the Moon. The moon takes 29 and 1/2 days to revolve around the Earth. This time period is called a month. A calendar month has 29 or 30 days. A year is the time it takes the Earth to make one revolution around the Sun, or 365 and 1/4 days. A calendar year is 365 days, except for every four years when it is 366 days.
This calendar serves well enough for living on the Earth, but what if we went to another planet. Could we use the same calendar? Each planet has a different rotation and revolution time. Some planets take much longer to make a rotation. Some planets rotate in less than one Earth day.
Imagine that you and your group are space colonists, and will be among the first people to live on a new planet. It is your job to invent a calendar for the new planet. The planet rotates once every 42 hours, and makes 156 rotations for every one revolution around the Sun. The moon makes one revolution around the planet every 12 days.
Make a calendar and clock for this planet:
1. How long will the year be?
2. How long is the day? How is the day divided?
3. How many days in a week? And how many months in the year?
4. Decide what you will call the months, and how you will name the days in a week.
5. Make a calendar for one year on the planet.
Materials: resources on counting systems , words for days of the week and months of the years in different languages, butcher paper, colored markers, rulers
1. Read above assignment and answer questions in journal.
2. Discuss answers and possible solutions to assignment.
4. Make calendars with butcher paper and markers.
5. Present and compare calendars.
Within the content of the presentation, answer the following questions:
1. How long is one year on the planet?
2. How many divisions are there in one year?
3. How did you divide the month?
4. How long is one day on the planet ? How did you divide the day?
5. How did you group the days?
6. How did you decide what to call the months and the days of the week and why?
7. When will the year begin on the planet and why?
8. Why did you choose to divide the time like you did?
9. What is the purpose of a calendar and how does the calendar you made serve this purpose for life on the imaginary planet?
extension: Aztec Sun Stone Project
image credit: http://www.nasa.gov/