ZERO-IN

Italicized font represents information to be shared orally or physically completed with the students at this time.

The non-italicized font represents additional information included to support the teacher’s understanding of the content being introduced within the CELL.

ANALYZE IT

Instruct students to complete the Analysis Questions in their SDRs then discuss them as a class. Use the suggested responses below to guide students’ answers.

• Describe the movement of the Sun, Moon, and Earth in our solar system. The Sun is at the center of our solar system. The Earth revolves around the Sun while rotating on its axis. While the Earth revolves and rotates, the Moon revolves around the Earth.

Note: Questions marked with a triangle (∆) are included to enrich students’ understanding. These questions do not appear in students’ SDRs but should be used as additional discussion points during the PostLab.

Tell students that, like most models, the simulation that students performed was not a perfect representation of the Earth, Moon, and Sun. Instruct students to discuss the following question in their group.

• ∆ What are some ways in which the model did not accurately represent the relationships between the Earth, Moon, and Sun? The actual Sun is a powerful light source that gives off a great amount of light and heat energy in all directions, unlike the flashlight, which only gives off minimal light in one direction. For this reason, the student representing the Sun had to shine the light directly on the Moon, rather than keeping the Sun completely stationary. Because of the limitations of the equipment used in the model and the limited space available for the simulation, the Earth did not revolve around the Sun. The model instead emphasized the rotation of the Earth and the revolution of the Moon in relation to the position of the Sun. In the second part of the simulation, the Earth only rotated once on its axis. The Earth only rotated once so that the student representing the Earth would not become dizzy.

• ∆ Did the simulation of the Moon’s phases have value to you in spite of the imperfections of the model? Student answers will vary. Students should respond that the model is valuable in spite of its imperfections. Through the model, students were better able to conceptualize the Moon phases as governed by the movement of the Moon in relation to the Earth and the Sun. Although the model was imperfect, it still aided students in visualizing each phase of the Moon.

Instruct students to recall the first part of the simulation when the student representing the Earth rotated on the stool as the Moon revolved around the Earth.

• ∆ Based on your model, how many days does it take for the Moon to complete one revolution around the Earth? In the students’ model, the Earth rotated seven times as the Moon completed one-quarter of a revolution. Continuing at this rate, the Moon would complete one full revolution in 28 days.

• What allows us to observe the different phases of the Moon from the Earth? The revolution of the Moon around the Earth allows us to see the different phases.

• ∆ What caused the illumination of the Moon? The Sun illuminated the Moon. The Moon produced no illumination of its own.

• During one complete revolution of the Earth, how much of the Moon, or how many of the Moon’s surfaces, were you able to see? As the Moon revolved, only one surface of the Moon was observed. The surface of the Moon with the piece of tape on it was the only surface that was ever observed, regardless of the phase of the moon. This is what we call the near side of the moon.

Tell students that their simulation modeled four of the Moon’s phases. These phases are known as the new moon, first quarter, full moon, and last quarter.

• ∆ What each phase of the Moon should be assigned to each of the four positions in their simulation? The first position of the Moon illustrated a new moon. The second position of the Moon was the first quarter. The third position of the Moon illustrated a full moon, and the last position was the last quarter. Ask students to record the names of the moon phase in Table A if they have not already done so.

• ∆ What causes the phases of the moon? The position of the Sun, Earth, and Moon cause the phases of the moon. When the Moon is between the Earth and the Sun, the Sun shines on the side of the Moon that is not facing the Earth. In this position, we on the Earth cannot see the Moon, since the side near us is not illuminated. When the Moon is opposite the Earth from the Sun, the Sun shines directly on the Moon, enabling us to see the entire surface of the Moon which is facing us. In this position, the Moon looks like a full circle. In all other positions of the Moon, the Sun shines on some portion of the surface of the Moon which faces the Earth. In these positions, the Moon appears not as a full circle but as a portion of a circle.

• What phases did you see between Tape A and Tape B positions? Draw and explain your answer. The phase is Waxing Crescent.

• What phases did you see between Tape C and Tape D positions? Draw and explain your answer. The phase is Waning Gibbons. 

• In what phase is the Moon not visible? During the New Moon phase, the Moon is not visible. 

• How many days are between the First Quarter and Full Moon phases? There are seven days between the First Quarter and Full Moon phases.

GET FOCUSED

Instruct students to complete the Focus Question in their SDRs then discuss it as a class. Use the suggested response below to guide students’ answers.

• Based on your model, why do you think we observe different phases of the Moon from the Earth? The position of the Sun, Earth, and Moon cause the phases of the moon. When the Moon is between the Earth and the Sun, the Sun shines on the side of the Moon that is not facing the Earth. In this position, we on the Earth cannot see the Moon because the side near us is not illuminated. When the Moon is opposite the Earth from the Sun, the Sun shines directly on the Moon, enabling us to see the entire surface of the Moon, which is facing the Earth. In this position, the Moon looks like a full circle. In all other positions of the Moon, the Sun shines on some portion of the surface of the Moon which faces the Earth. In these positions, the Moon appears not as a full circle but as a part of a circle. Different patterns of a circle appear to be illuminated at different times because of the revolution of the Moon around the Earth and our perspective from the Earth.