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Discovery Techbook - Unit: Space Systems / Concept: Phases

****NOTE: Watch ALL embedded video clips and images as you progress through each page of the concept.****

***ENGAGE- Answer all questions in COMPLETE SENTENCES where appropriate. Watch all video clips and images.

Complete PHASES on the Engage page then answer the questions below.

1. Which statements are correct about moon phases? Select all correct answers.a. Full moons generally occur once a weekb. Full moons generally occur once a monthc. A full moon is the name of the phase used when a full circle is seend. A full moon is the name of the phase used when a full sphere is seene. A new moon occurs once a weekf. A new moon occurs once a monthg. A new moon is the name of the phase used when a full circle is seenh. A new moon is the name of the phase used when no part of the moon that we see from Earth is lit

The role of the sun in moon phases

2. This concept is about the phases of the moon. However, you also will learn about the sun. What is the connection between the sun and the phases of the moon?_________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

3. Describe the different shapes of the moon you have observed in the night sky. You also may draw the different shapes you have seen.

4. Why do you think we see different shapes of the moon at night?_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

***EXPLORE p1/2- Answer all questions in COMPLETE SENTENCES where appropriate. Watch all video clips and images. How Does the Appearance of the Moon in the Sky Change over Time? / How Does the Moon Move in Space?

The lunar cycle describes the order in which the moon’s phases happen. It is the name given to the pattern of change in the moon’s appearance. It is called a cycle because______________________________________. A full cycle is completed when the moon goes from one new moon phase to the next new moon phase.

The lunar cycle can be divided into eight phases:

Write the Can You Explain question here:

1. _________________________ : During the new moon, the entire side of the moon facing us is dark.2. _________________________ : We see only a sliver of the moon illuminated.3. _________________________ : We see a half-circle. Half of the side of the moon facing us is lit.4. _________________________ : The moon is more than half illuminated, but is not yet full.5. _________________________ : The side of the moon facing us is fully illuminated by sunlight.6. _________________________ : The moon is again more than half illuminated, but not full.7. _________________________ : Half of the side of the moon facing us is lit. This is the half that is not lit during

the first quarter.8. _________________________ : The last sliver of the moon is illuminated.

The cycle then repeats with the appearance of another new moon.

Label the moon phases in the diagram below

The full lunar cycle takes ______ days. Although the moon appears to change shape, it is actually always a ________. In addition, although the apparent shape and location of the moon change from night to night, we always see the same _____________. Why? The moon _______ and _______ at the same rate so the same side always faces Earth!

The term “________” refers to a moon that is growing in illumination. The term “__________” refers to a moon that is shrinking in illumination. Draw an imaginary line down the center of the moon at night. If the side that is illuminated would fill in the shape of a “p”, think of it as ___________ on the way to a full moon or a “b” for _________ its cycle. If it fills in the shape of a lower case “d”, it’s on its way to ___________. This repeating pattern is the basis for a unit of time – __________________________.

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Moon Time

Imagine you need to track the passing of time (days, weeks, months) just from watching the night sky. What could you determine about time, now that you know the phases and length of the lunar cycle? Match the lengths of time to the description of what you have seen in the night sky.

1. Some time has passed since the full moon. There is no moon visible in the sky.___________________________________________________________________________________

2. The moon had just a sliver of light on its left side. Now it has just a sliver of light on its right side.___________________________________________________________________________________

3. You have seen a first-quarter moon three times now.___________________________________________________________________________________

4. The moon was just a sliver of light on its right side. Now it’s just a sliver of light on its left side.___________________________________________________________________________________

5. Some time has passed since the waxing gibbous moon. The moon is a waxing gibbous moon again.________________________________________________________________________________a. 3 months have passed b. about two weeks have passed c. one month has passed

d. about 3 weeks have passed e. about one week has passed

The moon’s orbital path is not on the same plane as ________ orbital path around the sun, it is at an incline. The moon’s orbital path is tilted 5 degrees. This is why we do not have eclipses every month. As a result, its __________ in the sky changes from night to night.

Students may think the phases of the moon are caused by Earth’s shadow on the moon or by the rotation of the moon. Actually, the phases occur because from Earth we see different areas illuminated by the sun as the moon revolves around Earth. Half of the moon is always illuminated, we just don’t see it from our viewpoint. What moon phase do we call it when we do see the half that is illuminated? _________________________

Explaining the moon phases

Study the image. Using what you have learned about the phases of the moon, write a short paragraph in the space below explaining what the image shows and what causes the phases.

***EXPLORE p3- Answer all questions in COMPLETE SENTENCES where appropriate. Watch all video clips and images.

Why Does the Moon Have Different Phases?

The moon itself does not emit its own ________. It shines because it’s highly reflective surface reflects the sun’s light back to _______. Sunlight only reaches the half of the moon’s surface that is facing the sun.

As the moon orbits Earth, the arrangement of the sun, Earth, and moon in space change. For example, sometimes the moon is between the sun and Earth (__________). A _______________ is visible when Earth is between the sun and the moon. Sometimes the Earth, moon, and sun form a _________. The phase of the _____ depends on its _______ relative to the sun and Earth. The phases change as the moon revolves around Earth, different portions of the moon’s sunlit surface are visible from Earth. Thus, from the perspective of Earth, the appearance of the moon changes from night to night.

Not only does the apparent shape of the moon change, its _____________________ also changes. This is also a result of how it moves in space. The change in position over the course of one night is a result of Earth’s rotation. As Earth rotates from west to east, everything in the sky, including the moon, appears to rise in the ______ and set in the _______. However, although the time at which the ________ rises and sets varies little from day to day, the moon rises and sets at noticeably different times. Since the moon completes one revolution around Earth in _______ days, it moves eastward about _________ degrees along its orbit of Earth each day. As a result, the moon appears to rise about ______________ later each night than the previous night.

The moon takes about _______ days to orbit Earth. A full lunar cycle, however, takes ______ days. This difference between the moon’s orbiting time and a full cycle of phases is because the moon is orbiting Earth as Earth is orbiting the sun. As a result, the moon must travel a little bit farther around Earth to catch up with its relative starting position.