Lunar Cycle. About This Lesson Phases of the Moon

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1 Lunar Cycle Misconcep on Alert: The Lunar Cycle is o en mistaken with the Luna Month. Here is the difference. The Lunar Cycle includes all 8 phases, including the New Moon phase (invisible at night because it tracks in the day sky only). A Lunar Month does not include the New Moon phase, but instead only the visible phases of the moon we see at night (so only seven of the eight phases). For this reason a lunar month is only 28 days long. Another misconcep on is that the length of the calendar months are based on the phases of the moon (lunar cycle). This is false because in the Gregorian Calendar ( days) four months have 30 days (Sept., April, June, Nov.) seven months have 31 days (Jan., March, May, July, Aug., Oct. and Dec.) and February has 28 or 29 days depending on the type of year (February has 29 days in a Leap Year). It is important to note that both of these misconcep ons occur all over the internet (including encyclopedia sites). So why do we need a lunar month anyway? It is likely this defini on began with our agricultural roots when farmers used the visible night sky to guide when to plant or harvest their crops. About This Lesson Phases of the Moon At the New Moon phase, the moon is lined up between the Earth and the Sun and only appears in the day me sky from Earth. We see the moon early in the morning at sunrise (or dawn) or late in the a ernoon at sunset (dusk). But most of the day, the Sun outshines the Moon. This is because the side of moon we see is not being lit by the Sun (in other words, we see no moon at all, because the brightness of the Sun outshines the dim moon). At night, during the New Moon phase, there is no moon in the night sky because as the Earth rotates into night, the moon is out of view from the night side of the Earth. As the lunar cycle con nues, the moon starts being waxed in sunlight. Waxing means to grow in sunlight. 3.5 days into the month we see the Waxing Crescent phase. 3.5 days a er the crescent, half of the moon is illuminated in the First Quarter phase. 3.5 day a er the First Quarter phase comes the Waxing Gibbous and the moon appears even more lit. The gibbous moon appears to grow fa er each night un l we see the full sunlit face of the moon. We call this phase the Full Moon. It rises almost exactly as the Sun sets and sets just as the Sun rises the next day. The Moon has now completed one half of the lunar cycle. During the second half of the lunar cycle, the moon grows thinner each night. We call this waning. The shape of the Moon is a Gibbous at this point, but it is growing a li le thinner each night so it is called the Waxing Gibbous moon. As moon reaches the Three Quarter point in its cycle, the Moon once again shows us the opposite half of its disc illuminated with the other half in darkness. [The side that we saw dark at the first quarter phase is now the lit side] As the moon completes its lunar month and approaches New Moon again, the Moon is a Waning Crescent. Then the lunar cycle repeats itself again beginning with the New Moon phase.

2 Lunar Cycle Standard: SC.4.E.5.1 Describe the changes in the observable shape of the moon over the course of about a month Procedure: 1. Read The Lunar Cycle.Next review each phase of the moon on the Lunar Cycle Clock. 2. Read the Moon Phases handout. 3. Follow the directions on the Moon Phases Calendar. 4. Use your Lunar Cycle Clock and Moon Calendar to calculate the answer for each problem. Then circle the best answer.

3 The Lunar Cycle Phases of the Moon The Moon has phases because it revolves around (orbits) the Earth. This causes the por on of the moon we see lit up by the Sun to change. The Moon takes 27.3 days to orbit the Earth. But, it takes 29.5 days to go from one Full Moon to the next. This is called one lunar cycle. During one lunar cycle, the Moon goes through 8 phases; New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Third Quarter, and Waning Crescent. You can see all eight phases in the lunar cycle diagram below. Diagram 1: The Lunar Cycle Just like the Earth the Moon is a sphere, so half of the Moon is lit by the Sun while the other half is in darkness. The phases of the Moon we see at night are a result of the angles the Moon forms with the Sun as we see it viewed from Earth. The acute, right, or obtuse angles are shown in the diagram below. right acute obtuse Diagram 2: Angle the moon forms with the sun as seen from the Earth

4 Sun New Moon Third Quarter First Quarter Full Moon

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6 Moon Phases Calendar NAME: #: Number the days of the month. For each day, observe the moon, then draw its phase. Sun Mon Tue Wed Thu Fri Sat

7 Name: Date: Lunar Cycle Math Practice Problems Use your Lunar Cycle Clock to calculate the answer for each problem. Then circle the best answer. 1) Jacob s teachers read this nursery rhyme about the months of the year to her class, 30 days has September, April, June, and November, all the rest have 31 except February. If November 1 st is a New Moon, what phase of the moon will it be on November 16 th? A. Waxing Crescent B. First Quarter C. Waxing Gibbous D. Full Moon 2) A blue moon is the second Full Moon in the same month. If January 1 is a Full Moon, could there be a Blue Moon in January? A. Yes, on January 25 to 27 B. Yes, on January 29 to 31 C. No, the next full moon is February 2 D. No, the next full moon is February 4 3) The harvest moon is the Full Moon closest to the fall equinox. If September 22, is the fall equinox and there is a First Quarter moon, what date is the harvest moon? A. September 26, 2016 B. September 29, 2016 C. October 1, 2016 D. October 3, ) If December 1 is the full cold moon or first Full Moon of the winter. When is the next Full Moon? A) December 3, Advent B) December 25, Christmas C) December 28, Denzel Washington s birthday, D) December 31, New Years Eve 5) In May the flowers come into full bloom and corn is ready to plant. Some American Indian tribes called the Full Moon in May the flower moon. If the flower moon is on May 22, 2016, when is the Third Quarter moon? A. May 26, 2016 B. May 29, 2016 C. June 12, 2016 D. June 27, 2016