A Year Viewed From Space
Teacher exemplar
A YEAR VIEWED FROM SPACE
SUGGESTED ANSWERS TO ANALYSIS QUESTIONS
1. What motion of the Earth causes the yearly cycle of the seasons? (CS Assessment)
Level 3 Response: Earth’s orbiting (or revolving) around the sun causes a year.
2. Why does a year on Earth have 365 1/4 days? (CS Assessment)
Level 3 Response: The Earth has 365 ¼ days in a year because the Earth rotates slightly more than 365 times during one revolution around the Sun (or year).
3. In which months is Earth: a. closest to the Sun? (CS Assessment)
Level 3 Response: Of the months investigated, Earth is closest to the Sun in December, when the distance is approximately 147 million km. (NOTE: The actual closest distance occurs in early January.)
b. farthest from the Sun? (CS Assessment)
Level 3 Response: Of the months investigated, it is farthest away in June, at 152 million km. (NOTE: The actual farthest distance occurs in early July.)
4. Based on what you have observed about the distance from Earth to the Sun, does the distance from Earth to the Sun determine the seasons? Explain the evidence for your answer. (AD ASSESSMENT)
Level 3 Response: The distance from Earth to the Sun does not determine the seasons. The Northern Hemisphere’s summer starts in June, when Earth is about 5 million km farther from the Sun than in December. If distance determined the seasons, we would have summer in December and winter in June. Also, if distance determined seasons, all parts of Earth would experience the same seasons at the same time and the seasons in the Northern and Southern hemispheres would not be reversed.
5. In what month is the Northern Hemisphere most tilted toward the Sun? (CS Assessment)
Level 3 Response: The Northern Hemisphere is most tilted toward the Sun in June.
6. In what month is the Northern Hemisphere most tilted away from the Sun? (CS Assessment)
Level 3 Response: The Northern Hemisphere is most tilted away from the sun in December.
7. Explain how the tilt of Earth affects the seasons and daylight hours. (UC Assessment)
Level 3 Response: When the Northern Hemisphere is tilted toward the Sun, it receives the Sun’s rays more directly (making it warmer), and the Sun is above the horizon for a longer period of time each day (which also makes the day longer and helps to make it warmer). When it is tilted away from the Sun, it receives less direct Sun and the day is shorter, so the temperature is cooler.
Teacher Exemplar for data found on simulation: