Phases of the Moon

The Moon The Moon is Earth’s one natural satellite and is more than ¼ the size of the Earth itself. Due to its smaller size and slower speed of rotation, the Moon’s gravity is 1/6 of the Earth’s gravity pull.

Revolution of the Moon The Moon revolves around the Earth The Earth revolves around the Sun The Moon passes through phases during a cycle that repeats itself every 29.5 days. As this occurs, some of the sun’s light is blocked by the moon’s shadow or by the Earth’s shadow.

Rotation of the Moon The moon rotates on its axis approximately every 27.3 days The moon rotates on its axis at about the same rate that it revolves around the Earth

The “Light” of the Moon The Moon does not generate any light itself; it just reflects the light of the Sun.

Moon Phases The Moon does not produce its own light, but looks bright because its surface reflects light from the Sun. As the Moon orbits the Earth, the amount of the lighted surface that is visible from Earth changes. This causes the shape of the visible surface to change and give us the phases of the moon.

Moon Phases The Moon passes through 6 phases during a cycle: New Moon Waxing Crescent First Quarter Waxing Gibbous Full Moon Waning Gibbous Last Quarter Waning Crescent

New Moon The New Moon lies between the Earth and the Sun because the sunlit side of the Moon is away from the Earth. The New Moon is invisible to us.

Waxing Crescent As the Moon moves along its orbit, it appears as a crescent on the right side. As the visible part of the moon grows, it is said to be “waxing.”

First Quarter The Moon has now completed a quarter of its orbit and appears to us as a half circle.

Waxing Gibbous When more than half of the sunlit side of the Moon is visible, the Moon is “gibbous.”

Full Moon The Moon reaches the second quarter of its orbit. The entire daylight side is visible and appears to us as a circle.

Waning Gibbous As the sunlit side of the Moon turns away from us, the Moon begins to “wane”.

Last Quarter The Moon reaches the third quarter of its orbit and appears as a backwards “D”.

Waning Crescent The visible portion of the Moon dwindles to a crescent. The fraction of the Moon’s disk that is illuminated is decreasing.

The Effect of the Phases of the Moon on the Tides Spring Tides occur when the sun, the Earth and the moon are horizontally in line. During this time the high tides are the highest and the low tides are the lowest. Neap Tides occur when the sun, the Earth and the moon are at 90o angles. There is less of a difference in high tides and low tides during this time.

Eclipse of the Moon Lunar Eclipse is when the Earth’s shadow falls upon the moon. Solar Eclipse is when the Moon’s shadow falls upon the Earth. An eclipse occurs at those times when the Moon moves into a position of direct alignment with the Sun and the Earth. 3D Simulation Eclipses

Total Lunar Eclipse A total Lunar Eclipse occurs when the full Moon passes through the shadow of the Earth. In this case, the Sun and the Moon are on opposite sides of the Earth. A lunar eclipse is only visible at night time of certain full Moons. A lunar eclipse can last as long as an hour.

Total Solar Eclipse A Total Solar Eclipse occurs when the new Moon passes directly between the Sun and the Earth. Daytime briefly turns to an eerie darkness, and during these few precious minutes the wispy halo of the Sun’s corona, comes into view as the dark disk of the Moon totally obscures the bright Sun.

Questions & Discussion

Questions & Discussion The moon rotates on its axis and revolves once around the Earth at the same rate which causes A. day and night B. the same side of the moon to always be visible from Earth C. the tides to change D. opposite sides of the moon to be visible from Earth

Questions & Discussion The moon rotates on its axis and revolves once around the Earth at the same rate which causes A. day and night B. the same side of the moon to always be visible from Earth C. the tides to change D. opposite sides of the moon to be visible from Earth

Questions & Discussion 1. Explanation Because the rotation and revolution of the moon around the Earth happens at approximately the same rate only one side of the moon is ever visible from Earth. Follow the path in your mind to understand this concept

Questions & Discussion The moon and the sun appear to move across the sky each day because of A. the Sun’s movement in the sky B. the Earth’s revolution around the sun C. the Earth’s rotation on its axis D. the Moon’s shadow on the Earth

Questions & Discussion The moon and the sun appear to move across the sky each day because of A. the Sun’s movement in the sky B. the Earth’s revolution around the sun C. the Earth’s rotation on it’s axis D. the Moon’s shadow on the Earth

Questions & Discussion 2. Explanation Because the Earth rotates on its axis causing day and night, the moon and sun appear to move across the sky. Our position on the Earth is what is actually changing.

Questions & Discussion How often do Spring tides and Neap tides each occur? A. two times a month B. two times a day C. two times a year D. four times a year

Questions & Discussion How often do Spring tides and Neap tides each occur? A. two times a month B. two times a day C. two times a year D. four times a year

Questions & Discussion 3. Explanation Because the moon takes approximately a month to revolve around the Earth and is in line horizontally two times and at a 90o angle two times during this period each of the types of tides (Spring and Neap) occur two times a month.

Questions & Discussion What is the best way to arrange the following words into the concept map below (phases, eclipse, solar eclipse, revolution, and lunar eclipse) A. phases, revolution, eclipse, solar eclipse, & lunar eclipse B. eclipse, solar eclipse, lunar eclipse, phases, & revolution C. lunar eclipse, revolution, eclipse, solar eclipse, & phases D. revolution, phases, eclipse, solar eclipse, 1 2 3 4 5

Questions & Discussion What is the best way to arrange the following words into the concept map below (phases, eclipse, solar eclipse, revolution, and lunar eclipse) A. phases, revolution, eclipse, solar eclipse, & lunar eclipse B. eclipse, solar eclipse, lunar eclipse, phases, & revolution C. lunar eclipse, revolution, eclipse, solar eclipse, & phases D. revolution, phases, eclipse, solar eclipse, 1 2 3 4 5

Questions & Discussion Revolution 4. Explanation of the moon around the Earth results in phases of the moon which may result in an eclipse such as a solar eclipse lunar eclipse

Questions & Discussion 5. At which position on the diagram above does the waning gibbous phase of the moon occur? A. 1 B. 2 C. 3 D. 4

Questions & Discussion 5. At which position on the diagram above does the waning gibbous phase of the moon occur? A. 1 B. 2 C. 3 D. 4

Questions & Discussion 5. Explanation: After the full moon which is between stages 2 and 3, the moon begins the waning stage and it first passes through a gibbous before the half and crescent stages, therefore number 3 – C is the correct answer

Questions & Discussion 6. Susan is sketching the appearance of the moon each night. Below is her entry for last night. What will Susan’s entry look like in 14 days? A. Image A B. Image B C. Image C D. Image D

Questions & Discussion 6. Susan is sketching the appearance of the moon each night. Below is her entry for last night. What will Susan’s entry look like in 14 days? A. Image A B. Image B C. Image C D. Image D

Questions & Discussion 6. Explanation: Answer choice D is correct because in 14 days the moon will have gone through ½ of it’s cycle and will basically be in the opposite phase as it is when Susan illustrates the moon phase.

Questions & Discussion 7. Mrs. Gupta is the Cub Scout den mother. She is taking a troop of boys on a camp out and believes it will be easier if she schedules the outing to happen during the full moon. Last night she observed a waning gibbous moon. Approximately how many days will she have to wait before the next full moon? A. 7 B. 14 C. 21 D. 28

Questions & Discussion 7. Mrs. Gupta is the Cub Scout den mother. She is taking a troop of boys on a camp out and believes it will be easier if she schedules the outing to happen during the full moon. Last night she observed a waning gibbous moon. Approximately how many days will she have to wait before the next full moon? A. 7 B. 14 C. 21 D. 28

Questions & Discussion 7. Explanation: If you divide the phases up there is approximately 7 days between every other phase or 3.5 days between each phase which would give you 21 days until the next full moon from a waning gibbous. The waning gibbous is the phase just after the full moon therefore you have to go all the way around to get back to a full moon.