So far we've covered the motions and cycles of the stars and sun in the sky, here we'll discuss the motions and cycles of the moon (but not eclipses, which will be covered in the next presentation).
First, let's review the boring but necessary terminology from the online reading assignment, and then review with a picto-quiz.
Make sure you can distinguish between very similar terms:
- full moon and new moon (well, this should be self-explanatory).
- waxing phases and waning phases (waxing phases get more full over time, waning phases get less full over time).
- crescent phases and gibbous phases (crescent phases are less than half full, gibbous phases are more than half full)
- first quarter and third quarter moon (both of these are exactly "half-moons," but the first quarter moon is a waxing phase that occurs one-quarter of the way through its cycle of moon phases, while the third quarter moon is a waning phase that occurs three-quarters of the way through).
Which phase is this--full, or new? (Yes, this one is mean to be easy.)
Which phase is this? (Look carefully at the logo--Twilight: New Moon is not a new moon!) Crescent, quarter or gibbous? Waxing or waning?
Crescent, quarter or gibbous? Waxing or waning?
Crescent, quarter or gibbous? First or third?
Crescent, quarter or gibbous? Waxing or waning?
Crescent, quarter or gibbous? Waxing or waning?
Second, let's get to our Earth-moon diagram model of phases.
Consider the origin of the word "month." A "moonth" is the time for the moon go through its phases, which is approximately four weeks, or...a month.
One last synchronizing activity--when a given time of day occurs, you all say "now." Keep in mind that the rotation of Earth and the revolution of the moon occur at the same time, and this is what makes the moon rise and set at different times of day, depending on its phase. We'll practice using this Earth-moon diagram on an in-class activity to determine these patterns.
2 comments:
The Earth is not rotating or tilting in the Dr. Evil clip!
The giant "laser"
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