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1. Use your textbook to define the word astronomy.
Lesson Essential Question:How does Earth’s movement impact our daily lives?
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•Go over bellringer•Vocab Previewing•Rotation vs. Revolution Vocabulary Discussion•Rotation vs. Revolution Simon Says Activity•Calendar discussion and notes
•Stand beside your partner
•Listen for Rotation, Revolution, or Both to be called!!
•Rotation – Both partners spin in place.
•Revolution – Earth partner circles around sun partner.
•Both – Earth partner spins and circle sun partner.
The calendar is a system of organizing time that defines the beginning,
length, and divisions of a year.
No one knows who invented the first calendar.
No one knows when the first calendar was invented.
Notched bones recording moon phases have been found in Africa and Europe.
They are from 20,500 B. C. WOW, that’s old!
Our calendar started with the ancient Egyptians.
The Egyptians based their calendar on the sun because of their belief in the sun god Ra.
https://www.youtube.com/watch?v=kzprsR2SvrQ
• Julius Cesar - famous Roman Emperor wanted a new calendar.
• Picked the Egyptian calendar and changed it a little bit.
• Julius Caesar expanded the Roman empire until it covered parts of Africa, Asia and Europe.
• As the empire grew, the calendar went with it. That is why European countries use this calendar.
The USA was settled by European colonists who brought the calendar with them.
That’s why we use Julius Caesar’s calendar!
The Julian Calendar
• Julian Calendar (adopted by Julius Caesar)– Year = 365.25 days long– Normal year = 365 days– Every 4 years there was one extra day in the
year. (.25 + .25 + .25 + .25)– Add leap day (Feb 29) every 4 years
• The Catholic Pope Gregory XIII (the thirteenth) changed the calendar again in 1582.
• Julius Caesar had counted wrong and the leap years needed to be changed or Easter would be in the middle of the summer!
The Gregorian Calendar
• Gregorian Calendar (adopted by Pope Gregory)– 10 day error accumulated by 1582
•October 4, 1582 followed by October 15, 1582
•10 days eliminated from calendar
The Gregorian Calendar • Modified leap day rules
– Year = 365.2425 days long– Normal year = 365 days– Add leap day (Feb 29) every 4 years– Remove one leap day every hundred years – Except every 400 years (so 2000 was a leap
year!)
Julius Caesar named the months of the year.
January- the Roman god Janus
February- the Roman purification festival Februa
March- the Roman god Mars
April- the old Roman calendar month of Aprilis
May- the Roman goddess Maia
June- the Roman goddess Juno
July- named after Julius Caesar
August- named for the Roman emperor Augustus
September- from the Latin septem which means seven
October- from the Latin octo or eight
November- from the Latin nove or nine
December- from the Latin decem or ten
So why does the ninth month mean seven, the tenth month mean eight, the eleventh month mean nine and
the twelfth month mean ten?
Julius Caesar’s calendar started with the month of March and ended with
the month of February.
That’s really strange, isn’t it?
English for Mercury’s day
Wotan’s day
Mercury was the Roman god of peace and prosperity
Wotan was the old English god of peace and prosperity
English for Jupiter’s day
Thor’s day
Jupiter was the king of the Roman gods
Thor was the old English thunder god
English for Venus’ day
Frigg’s day
Venus was the Roman goddess of love
Frigg was the old English goddess of love
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