Earth, Moon, Sun & Space Models — Problem set, Grade 6
How can one system contain different mechanisms, perspectives, and scales? Can one labeled model explain phases, seasons, eclipses, and scale without confusing their mechanisms?
Review the key ideas
The Solar System, Gravity & Orbits
Gravity is an attraction between any two masses, and it keeps planets in orbit for the same reason it makes an apple fall. An orbiting object is falling continuously; it simply moves sideways fast enough that it keeps missing what it is falling towards.
Day, Night & Seasons: Rotation and Tilt
Seasons are not caused by Earth's distance from the Sun. They are caused by the 23.5 degree tilt of its axis, which changes both the angle sunlight strikes the ground and how long the Sun is up, and the clearest proof is that the two hemispheres have opposite seasons at the same moment.
Moon Phases: Sunlight & Viewing Geometry
The Sun always lights exactly half the Moon. Phases are the changing fraction of that lit half we can see from Earth as the Moon moves round us, and they are not Earth’s shadow falling on it, which is a different and far rarer event.
Eclipses & Tides: Alignment with Different Mechanisms
Eclipses and spring tides both happen when the Sun, Earth and Moon line up, and they are produced by entirely different physics. An eclipse is a shadow, which is light travelling in straight lines; a tide is gravity pulling harder on one side of Earth than the other.
Space Models: Scale, Evidence & Revision
Almost every picture of the solar system you have ever seen is wrong about distance, because no diagram can show both the sizes of the planets and the gaps between them. Building a scale model to honest numbers is the quickest way to discover what space is actually like, which is overwhelmingly empty.
Problem 1
Answer and explanation
A is the better basic explanation. Gravity changes the moving satellite’s direction rather than vanish outside the atmosphere. Without the modeled force, its motion would not follow the same curved path around Earth. The drawing still omits precise speed, distance scale, and other influences needed for a full numerical prediction.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 2
Answer and explanation
No. It may emphasize order or relationships. Use labeled diameter data and a stated scale rather than infer real sizes from an unscaled sketch.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 3
Answer and explanation
Summer gives 840 units per area per day and winter 350. Both longer daylight and the larger modeled received rate contribute. These illustrative values explain an energy mechanism, not a guaranteed daily temperature, and real clouds, surface properties, and seasonal response also matter.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 4
Answer and explanation
No. Weather varies within seasons. The geometry concerns a broader illumination pattern, not a guarantee that every summer day is warm.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 5
Answer and explanation
The visible illuminated fraction grows from new toward full and then decreases toward last quarter. About half the Moon remains sunlit throughout; the viewing fraction changes. Eclipses need additional alignment with the tilted orbit, so the full-phase entry does not guarantee Earth’s shadow crosses the Moon.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 6
Answer and explanation
No. Its rotation is coordinated with its orbital motion. A model must include both to explain the familiar facing side.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 7
Answer and explanation
The diagram represents a possible solar eclipse if alignment is exact. A’s range is 4.5 m and B’s 2.0 m. Tides involve gravitational effects, not a shadow lifting water. The table is fictional and cannot plan a real shore visit, and an alignment drawing does not guarantee an eclipse at every new phase.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 8
Answer and explanation
No. Full phase supplies the broad Sun–Earth–Moon arrangement, while orbital tilt can prevent the Moon entering Earth’s shadow.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 9
Answer and explanation
The consistent values are 150 cm to the Sun, 0.384 cm or 3.84 mm to the Moon, and Earth diameter 0.0127 cm or 0.127 mm. The poster’s 2 cm Earth and 10 cm Moon separation do not follow that scale. Label its size and spacing as exaggerated for relationship viewing rather than present it as a numerical distance model.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 10
Answer and explanation
No. It may be useful for illumination geometry if its limits are stated. It should not be used for numerical distance or diameter comparisons without the appropriate scale.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.