This packet is everything a parent or guide needs to assess Unit 04 at home — learning targets, the answers that count as correct, the mastery rubric, calibration examples, and a clipboard score sheet. No multiple-choice test: the student shows mastery by building a scale model of the solar system and reasoning from orbits and gravity aloud.
By the end of the Solar System unit, a student should be able to:
Six criteria, each judged Not yet / Approaching / Mastered (Page 3).
Build a model that honors relative sizes and distances.
The student reasons from orbits and gravity aloud (Page 4).
Dated sketches of the visible planets kept across weeks.
You are making a decision, not adding up points. For each criterion, decide whether the work is Not yet, Approaching, or Mastered — the column language tells you which. A criterion counts as mastered only when the student can both build the model and justify the orbital reasoning behind it. A student carries three tokens per term; one token buys a re-do of one criterion on another night, so a single clouded-out evening never sinks the unit.
Accept any answer in the synonyms column — they are pre-approved as equivalent. The third column flags the confusions that look close but are not yet, so you can coach precisely.
| Canonical answer | Accepted synonyms | Common confusion / discriminator |
|---|---|---|
| Worlds & small bodies | ||
| Terrestrial planet | rocky inner world | Small and dense; Mercury through Mars |
| Giant planet | gas or ice giant | Large and low-density; Jupiter through Neptune |
| Kuiper belt | icy outer ring | Home of comets and dwarf planets beyond Neptune |
| Orbits & formation | ||
| Kepler's laws | ellipse, equal areas, period–distance | Govern orbital motion; orbits are ellipses, not circles |
| Ellipse | oval orbit | The Sun sits at one focus, not the center |
| Gravity | the force that binds orbits | Keeps planets falling around the Sun, not flying off |
| Solar nebula | collapsing gas-and-dust cloud | The disk the whole system formed from |
| Orrery | scale model of the system | Honors relative sizes and distances, not a tidy row |
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| The scale of the solar system | Pictures the planets as a tidy, evenly spaced row. | Knows the order but has no sense of the real distances. | Grasps the true scale — the vast gaps between worlds — and can build or describe a model that honors it. |
| Planets & their properties | Cannot distinguish the planets beyond their names. | Sorts them into rocky and gas but not by density or composition. | Contrasts terrestrial and giant planets by size, density, and composition, and explains why they differ. |
| Orbits, Kepler & gravity | Thinks orbits are circles and cannot say what holds them. | Says gravity holds orbits but treats them as perfect circles. | Explains orbital motion with Kepler's laws and gravity — ellipses, faster near the Sun, period tied to distance. |
| Small bodies — moons, asteroids, comets | Lumps every small body together. | Names moons, asteroids, and comets but not where they sit or how they formed. | Places moons, asteroids, comets, and Kuiper-belt bodies and explains how each formed. |
| Modeling & the journal | Skips the model and leaves the journal blank. | Builds a model but ignores true scale, or keeps thin, undated notes. | Builds an accurate scale model or orrery and logs dated observations of the visible planets across weeks. |
| Integration (cross-domain) | Treats the science as isolated facts. | Names a link to history, reading, or writing but cannot defend it. | Connects the unit across History · Reading · Writing and defends why it matters. |
The split between Approaching and Mastered is scale and shape over order: not reciting the planets, but honoring the vast gaps and the elliptical orbits. Ask “if Earth were this marble, where would Neptune be?”
Read these before you grade. They show what Mastered and Not yet actually sound like, plus the edge cases where you should coach rather than decide on the spot.
Student: ______________________________________ Date: _______________ Guide: _________________________
| # | Criterion | Decision | Notes |
|---|---|---|---|
| 1 | The scale of the solar system | NY / Appr / Mast | |
| 2 | Planets & their properties | NY / Appr / Mast | |
| 3 | Orbits, Kepler & gravity | NY / Appr / Mast | |
| 4 | Small bodies — moons, asteroids, comets | NY / Appr / Mast | |
| 5 | Modeling & the journal | NY / Appr / Mast | |
| 6 | Integration (cross-domain) | NY / Appr / Mast |
☐ No ☐ Yes — for criterion: __________ Tokens remaining: ☐ 3 ☐ 2 ☐ 1 ☐ 0
NY = Not yet · Appr = Approaching · Mast = Mastered · Unsure between two levels? Circle the lower one and note what a re-do would need.