Source Material for after the Test

1
Source Material for after the Test

• Friday (Lec 13) Eclipses
• CP 2.3 What causes eclipses?
• Monday (Lec 14) Choosing our Model of the Solar
  System
• CP 2.4 Why did the ancient Greeks reject the
  real explanation for planetary motion?
• CP 3.2 Ancient Greek science
• Focus on how the Greeks practiced science and on
  understanding their geocentric model of the solar
  system, not on the historical details
• CP 3.3 Copernican Revolution
• Focus on what the various new models were, and
  the pros / cons of each, not on historical
  details.
• Pay particular attention to why previous models
  were discarded, and how this fits into the
  discussion of how science works.
• SKIP Keplers Laws (well talk about them later)
• DO include the part about Galileo (pp. 75-78)
• CP 3.4 (review of how science works)
• This time notice how the various models were
  reviewed and discarded using the process of
  science

2
Moons Historical Importance

• Mayans had accurate but complicated calendar with
  precise tables for moon motion
• Our month based on lunar phases
• Many calendars still lunar (e.g. Muslim, Chinese)
• Africans related observations of moon cycles to
  rainfall patterns

3
2.5 The Moon, Our Constant Companion
Goals for learning

• Is the Moon bigger when it is near the horizon?
• Why do we see phases of the Moon?
• What are the various phases of the Moon?
• When / why do they happen?
• What is the relationship between time of day,
  location in sky, and phase of the moon?
• What is the view from the Moon of Earth?

4

• Near Side of the Moon

Dark Side of the Moon?
Dark Side of the Moon?
Far Side of the Moon
5
Why do we see the same face?

• Rotation period orbital period

6
Lunar Motion
Phases during the Moons 29.5 day cycle

• new
• waxing crescent
• first quarter
• waxing gibbous
• full
• waning gibbous
• last quarter
• waning crescent

7
Why do we see phases?

• Moon
• shines by
• reflected
• light

• Half the Moon illuminated by Sun and half dark
• We see some combination of the bright and dark
  faces

• http//jove.geol.niu.edu/faculty/stoddard/JAVA/moo
  nphase.html
• http//www.chabotspace.org/vsc/planetarium/themoon
  /moonphases/default.asp

8
Phases of the Moon - Example
Incoming sunlight
Why does sunlight come in parallel?
9

• Which Moon position best corresponds with the
  moon phase shown in the upper right corner of the
  picture?
• What about Full Moon?
• Why Full Moon is not blocked (applet more later)

10
Figuring Phases
What is the phase of the Moon if it is in the
circled location? Full A 1st Quarter B New
C 3rd Quarter D
Which side appears lit? Near A Far B Left
C Right D
11

• Which Moon position best corresponds with the
  moon phase shown in the upper right corner of
  Figure 1?

12
Phases of the Moon

• Full Moon
• Opposite Sun in Sky
• Crescent Moon
• Near Sun in Sky
• Gibbous Moon
• Far from Sun in Sky
• Moon moves eastward relative to stars / Sun each
  day
• Waxing seen at sunset
• Waning seen at sunrise

13
Phase vs. Location in Sky
14
Phase vs. Location in Sky
What time does a 1st quarter moon rise? Sunrise
A Noon B Sunset C Midnight D
15
Moon Motions

• Moon moves 13 degrees per night relative to the
  stars, due to its motion around the Earth

16
Question

• Sensible (A) or not (B)?
• Recently, I went out around midnight and saw the
  crescent moon high overhead

17

• If the Moon is a full moon when it rises in the
  evening, which of the phases shown below will be
  in when it sets?

18

• What is the Moons phase?
• What time will this moon appear highest in the
  sky?
• What time will it rise? Set?