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Exam #1 on Thursday
• Chapters 1, 2-1, 2-2 and S1-2
• 50 multiple choice questions
• Bring a pencil
• Bring a calculator – no cell phones
How are the motions and positions of
Earth and the Sun connected to what
happens on Earth?
• Earth’s rotation on its axis determines the length of
the day.
• Earth’s orbit around the Sun determines the length
of the year.
• The tilt of Earth’s rotational axis with respect to the
plane of Earth’s orbit causes the seasons.
The changing phases of the Moon originally
inspired the concept of the Month
Motion of the Moon
• Watch the moon night
after night, and you will
notice three things
– Over the course of about a
month, we see the moon
go through a series of
phases
– It is moving relative to the
background of stars
– The markings on its face
don’t change
The changing shape of the
illuminated part of the Moon as
it orbits Earth is one of the
most easily observed
phenomena in astronomy
Phases of the Moon: 29.5-day cycle
new
crescent
first quarter
gibbous
full
gibbous
last quarter
crescent
waxing
• Moon visible in afternoon/
evening.
• Gets “fuller” and rises later each
day.
waning
• Moon visible in late night/
morning.
• Gets “less” and sets later each
day.
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How long does it take to complete
the full cycle of Moon Phases?
