UST Middle School Science Challenge
Week 9 — Earth, Space & the Solar System
Grades 6–8 • Focus: Gravity, seasons, Moon phases, planets and stars
Weekly Format
Gravity, seasons, Moon phases, planets and stars
Part A — 15 Multiple Choice
Part B — 15 Fill in the Blank
Part C — 15 Scientific Reasoning / Open Response
Part D — 5 Challenge Problems
Answers and How to Solve are separated at the end.
Part A — Multiple Choice
Questions 1–5
1. The force keeping planets in orbit is? A) gravity B) an unrelated process C) none of these D) a different scientific idea
2. Earth’s seasons are mainly caused by? A) axial tilt B) an unrelated process C) none of these D) a different scientific idea
3. Moon phases result from? A) changing views of the sunlit Moon B) an unrelated process C) none of these D) a different scientific idea
4. A light-year measures? A) distance B) an unrelated process C) none of these D) a different scientific idea
5. The Sun is a? A) star B) an unrelated process C) none of these D) a different scientific idea
Part A — Multiple Choice
Questions 6–10
6. The force keeping planets in orbit is? A) gravity B) an unrelated process C) none of these D) a different scientific idea
7. Earth’s seasons are mainly caused by? A) axial tilt B) an unrelated process C) none of these D) a different scientific idea
8. Moon phases result from? A) changing views of the sunlit Moon B) an unrelated process C) none of these D) a different scientific idea
9. A light-year measures? A) distance B) an unrelated process C) none of these D) a different scientific idea
10. The Sun is a? A) star B) an unrelated process C) none of these D) a different scientific idea
Part A — Multiple Choice
Questions 11–15
11. The force keeping planets in orbit is? A) gravity B) an unrelated process C) none of these D) a different scientific idea
12. Earth’s seasons are mainly caused by? A) axial tilt B) an unrelated process C) none of these D) a different scientific idea
13. Moon phases result from? A) changing views of the sunlit Moon B) an unrelated process C) none of these D) a different scientific idea
14. A light-year measures? A) distance B) an unrelated process C) none of these D) a different scientific idea
15. The Sun is a? A) star B) an unrelated process C) none of these D) a different scientific idea
Part B — Fill in the Blank
Questions 16–20
16. Complete the statement: Moon phases result from ______.
17. Complete the statement: A light-year measures ______.
18. Complete the statement: The Sun is a ______.
19. Complete the statement: The force keeping planets in orbit is ______.
20. Complete the statement: Earth’s seasons are mainly caused by ______.
Part B — Fill in the Blank
Questions 21–25
21. Complete the statement: Moon phases result from ______.
22. Complete the statement: A light-year measures ______.
23. Complete the statement: The Sun is a ______.
24. Complete the statement: The force keeping planets in orbit is ______.
25. Complete the statement: Earth’s seasons are mainly caused by ______.
Part B — Fill in the Blank
Questions 26–30
26. Complete the statement: Moon phases result from ______.
27. Complete the statement: A light-year measures ______.
28. Complete the statement: The Sun is a ______.
29. Complete the statement: The force keeping planets in orbit is ______.
30. Complete the statement: Earth’s seasons are mainly caused by ______.
Part C — Scientific Reasoning
Questions 31–35
31. A student compares two conditions and records results over five trials. Explain how the idea “axial tilt” is relevant. Use 2–3 complete sentences.
32. A class observes a model and explains how its parts work together. Explain how the idea “changing views of the sunlit Moon” is relevant. Use 2–3 complete sentences.
33. Students examine a data table and notice a consistent pattern. Explain how the idea “distance” is relevant. Use 2–3 complete sentences.
34. A team changes one factor and measures the response. Explain how the idea “star” is relevant. Use 2–3 complete sentences.
35. A scientist compares evidence from two possible explanations. Explain how the idea “gravity” is relevant. Use 2–3 complete sentences.
Part C — Scientific Reasoning
Questions 36–40
36. A student compares two conditions and records results over five trials. Explain how the idea “axial tilt” is relevant. Use 2–3 complete sentences.
37. A class observes a model and explains how its parts work together. Explain how the idea “changing views of the sunlit Moon” is relevant. Use 2–3 complete sentences.
38. Students examine a data table and notice a consistent pattern. Explain how the idea “distance” is relevant. Use 2–3 complete sentences.
39. A team changes one factor and measures the response. Explain how the idea “star” is relevant. Use 2–3 complete sentences.
40. A scientist compares evidence from two possible explanations. Explain how the idea “gravity” is relevant. Use 2–3 complete sentences.
Part C — Scientific Reasoning
Questions 41–45
41. A student compares two conditions and records results over five trials. Explain how the idea “axial tilt” is relevant. Use 2–3 complete sentences.
42. A class observes a model and explains how its parts work together. Explain how the idea “changing views of the sunlit Moon” is relevant. Use 2–3 complete sentences.
43. Students examine a data table and notice a consistent pattern. Explain how the idea “distance” is relevant. Use 2–3 complete sentences.
44. A team changes one factor and measures the response. Explain how the idea “star” is relevant. Use 2–3 complete sentences.
45. A scientist compares evidence from two possible explanations. Explain how the idea “gravity” is relevant. Use 2–3 complete sentences.
Part D — Challenge
Questions 46–50
46. Challenge: Design or describe a short investigation that could demonstrate the concept “gravity.” Identify what you would observe or measure.
47. Challenge: Design or describe a short investigation that could demonstrate the concept “axial tilt.” Identify what you would observe or measure.
48. Challenge: Design or describe a short investigation that could demonstrate the concept “changing views of the sunlit Moon.” Identify what you would observe or measure.
49. Challenge: Design or describe a short investigation that could demonstrate the concept “distance.” Identify what you would observe or measure.
50. Challenge: Design or describe a short investigation that could demonstrate the concept “star.” Identify what you would observe or measure.
Answer Key — Questions 1–5
Answer + How to Solve
1. Answer: A
How to solve: Gravity attracts planets toward the Sun.
2. Answer: A
How to solve: Tilt changes sunlight angle and day length during orbit.
3. Answer: A
How to solve: Half the Moon is lit; our viewing angle changes.
4. Answer: A
How to solve: It is the distance light travels in one year.
5. Answer: A
How to solve: The Sun produces energy by nuclear fusion.
Answer Key — Questions 6–10
Answer + How to Solve
6. Answer: A
How to solve: Gravity attracts planets toward the Sun.
7. Answer: A
How to solve: Tilt changes sunlight angle and day length during orbit.
8. Answer: A
How to solve: Half the Moon is lit; our viewing angle changes.
9. Answer: A
How to solve: It is the distance light travels in one year.
10. Answer: A
How to solve: The Sun produces energy by nuclear fusion.
Answer Key — Questions 11–15
Answer + How to Solve
11. Answer: A
How to solve: Gravity attracts planets toward the Sun.
12. Answer: A
How to solve: Tilt changes sunlight angle and day length during orbit.
13. Answer: A
How to solve: Half the Moon is lit; our viewing angle changes.
14. Answer: A
How to solve: It is the distance light travels in one year.
15. Answer: A
How to solve: The Sun produces energy by nuclear fusion.
Answer Key — Questions 16–20
Answer + How to Solve
16. Answer: changing views of the sunlit Moon
How to solve: Half the Moon is lit; our viewing angle changes.
17. Answer: distance
How to solve: It is the distance light travels in one year.
18. Answer: star
How to solve: The Sun produces energy by nuclear fusion.
19. Answer: gravity
How to solve: Gravity attracts planets toward the Sun.
20. Answer: axial tilt
How to solve: Tilt changes sunlight angle and day length during orbit.
Answer Key — Questions 21–25
Answer + How to Solve
21. Answer: changing views of the sunlit Moon
How to solve: Half the Moon is lit; our viewing angle changes.
22. Answer: distance
How to solve: It is the distance light travels in one year.
23. Answer: star
How to solve: The Sun produces energy by nuclear fusion.
24. Answer: gravity
How to solve: Gravity attracts planets toward the Sun.
25. Answer: axial tilt
How to solve: Tilt changes sunlight angle and day length during orbit.
Answer Key — Questions 26–30
Answer + How to Solve
26. Answer: changing views of the sunlit Moon
How to solve: Half the Moon is lit; our viewing angle changes.
27. Answer: distance
How to solve: It is the distance light travels in one year.
28. Answer: star
How to solve: The Sun produces energy by nuclear fusion.
29. Answer: gravity
How to solve: Gravity attracts planets toward the Sun.
30. Answer: axial tilt
How to solve: Tilt changes sunlight angle and day length during orbit.
Answer Key — Questions 31–35
Answer + How to Solve
31. Answer: Response should correctly apply: axial tilt.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. Tilt changes sunlight angle and day length during orbit.
32. Answer: Response should correctly apply: changing views of the sunlit Moon.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. Half the Moon is lit; our viewing angle changes.
33. Answer: Response should correctly apply: distance.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. It is the distance light travels in one year.
34. Answer: Response should correctly apply: star.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. The Sun produces energy by nuclear fusion.
35. Answer: Response should correctly apply: gravity.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. Gravity attracts planets toward the Sun.
Answer Key — Questions 36–40
Answer + How to Solve
36. Answer: Response should correctly apply: axial tilt.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. Tilt changes sunlight angle and day length during orbit.
37. Answer: Response should correctly apply: changing views of the sunlit Moon.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. Half the Moon is lit; our viewing angle changes.
38. Answer: Response should correctly apply: distance.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. It is the distance light travels in one year.
39. Answer: Response should correctly apply: star.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. The Sun produces energy by nuclear fusion.
40. Answer: Response should correctly apply: gravity.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. Gravity attracts planets toward the Sun.
Answer Key — Questions 41–45
Answer + How to Solve
41. Answer: Response should correctly apply: axial tilt.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. Tilt changes sunlight angle and day length during orbit.
42. Answer: Response should correctly apply: changing views of the sunlit Moon.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. Half the Moon is lit; our viewing angle changes.
43. Answer: Response should correctly apply: distance.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. It is the distance light travels in one year.
44. Answer: Response should correctly apply: star.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. The Sun produces energy by nuclear fusion.
45. Answer: Response should correctly apply: gravity.
How to solve: Define the concept, connect it to the scenario, and cite the observation or measurement that supports the connection. Gravity attracts planets toward the Sun.
Answer Key — Questions 46–50
Answer + How to Solve
46. Answer: Answers vary; investigation must correctly demonstrate gravity.
How to solve: State a testable setup, identify the variable/measurement, predict an observable result, and explain why that result demonstrates the concept.
47. Answer: Answers vary; investigation must correctly demonstrate axial tilt.
How to solve: State a testable setup, identify the variable/measurement, predict an observable result, and explain why that result demonstrates the concept.
48. Answer: Answers vary; investigation must correctly demonstrate changing views of the sunlit Moon.
How to solve: State a testable setup, identify the variable/measurement, predict an observable result, and explain why that result demonstrates the concept.
49. Answer: Answers vary; investigation must correctly demonstrate distance.
How to solve: State a testable setup, identify the variable/measurement, predict an observable result, and explain why that result demonstrates the concept.
50. Answer: Answers vary; investigation must correctly demonstrate star.
How to solve: State a testable setup, identify the variable/measurement, predict an observable result, and explain why that result demonstrates the concept.