Calendars

CALENDARS.

The students and you can read a text showing the origin of our calendar and comparing it with other calendars. After reading each paragraph you can ask the following questions.

Questions about the first paragraph:

Which is the oldest? And the youngest?
What happened during the first day of our calendar? (Our calendar starts with Jesus Christ’s birth, although many historians think there is a mistake and Jesus Christ really was born 3 BC ¡!) (Explain the meaning of BC and AD)
What happened the first day of the Muslim Calendar? (Prophet Mohamed travelled from Mecca to Medina. It happened in 622).

Questions about the second paragraph:

Which astronomical references are used to measure the passing of time? (Day-night, lunar phases, seasons or year)
Which is the cause of the changing of days and nights? (Rotation)
What originates the lunar phases? (The movement of the Moon around the Earth)
Which is the origin of the change of seasons? (Revolution)

Questions about the third paragraph:

Why do we say that the Muslim calendar is not in sequence with the seasons? (The same month, for instance the sacred month of Ramadan, may belong to winter one year and to spring a few years later.)
Could we work out what year we are in the Muslim year by simply susbtracting 622 from the current year? Give reasons for your answer. (No, because Muslim calendar is not 365 days long)

Questions about the forth paragraph:

We still can find ordinal numbers in our months. Where? (September is like “séptimo”, October is “octavo, November is “noveno” and December is “décimo”)

Questions about the fifth paragraph:

Which is the month dedicated to Julius Caesar? (July, Julio)
What was July called before? (Quintilis)
Which is the month dedicated to Augustus Caesar? (August, Agosto)
What was its name? (Sextilis)
Romans wanted long months for these two emperors so July is 31 days long and August is 31 days long too. A month lost a pair of days. Which month? (February. Poor February!)

Questions about the sixth paragraph:

Why do we need leap years? (Because a solar year is almost a quarter day longer than a calendar year. So we have to add a extra day periodically in order to compesate this difference)
When does the last leap year occur? (Last year, in 2004.)

Questions about the seventh paragraph:

Which of the following years are leap years according with the Gregorian calendar? 1913 (No), 448 (Yes), 168 (No), 2004 (Yes), 2015 (No), 2018 (No), 2012 (Yes), 2100 (No), 2200 (No), 2300 (No), 2400 (Yes). (A number is multiple of four if its two last numbers are four o mutiple of four).

Finally, after proposing a new calendar that solves some old problems, you can ask:

Can you see the advantage of this calendar?
Would you like this change?
Do you think people will allow that change? Remember we have alredady suffered an important change when pesetas turned into euros.
We have to look for a name for the month numer 13. Any suggestion?
This calendar seems better but it also has a problem. If you muliply 13 y 28, the result is 364 days, not 365. What can we do? If you introduce another day the whole calendar will be ruined unless the new day didn´t have a number and a name of day of week. What would be its name? Maybe New Year Day, before the 1^st of January.
There is another problem, more personal. If you were born in March the 29^th, when would you celebrate your birthday?