This packet is everything a parent or guide needs to assess Unit 02 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 reconstructing the geocentric-to-heliocentric argument and tracking a planet across weeks.
By the end of the History of Astronomy unit, a student should be able to:
Six criteria, each judged Not yet / Approaching / Mastered (Page 3).
A planet's position logged over weeks under a red flashlight.
The student reconstructs the historical argument aloud (Page 4).
Dated sketches of a tracked planet 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 trace the historical reasoning and point to the observation that settled 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 |
|---|---|---|
| Models of the sky | ||
| Geocentric model | Earth-centered model | A reasonable fit: no felt motion, the sky wheels overhead nightly |
| Retrograde motion | apparent backward loop | The strain that broke the geocentric picture — apparent, not real |
| Heliocentric model | Sun-centered model | Explains retrograde more simply (Copernicus); acceptance came slowly |
| Ptolemaic system | epicycle geometry | Careful geometry that saved the geocentric appearances |
| Observation & the laws | ||
| Tycho Brahe's data | precise naked-eye records | The observations Kepler's laws rest on — no telescope |
| Kepler's laws | ellipses, equal areas, period–distance | Describe orbital motion, not perfect circles |
| Galileo's evidence | Jupiter's moons; phases of Venus | Direct evidence against an Earth-centered sky |
| Ellipse | oval orbit | Kepler's first law; the Sun sits at one focus, not the center |
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| The geocentric model & its logic | Dismisses the geocentric model as simply foolish or ignorant. | Says Earth was thought central but cannot say why that was reasonable. | Explains why an Earth-centered sky fit the evidence — no felt motion, the nightly wheeling — and where it strained against the planets' retrograde loops. |
| The shift to a heliocentric model | Cannot contrast the geocentric and heliocentric pictures. | Names Copernicus but treats the switch as mere opinion. | Shows how a Sun-centered model explains retrograde motion more simply, and explains why acceptance came slowly. |
| Tycho's data & Kepler's laws | Does not connect observations to the laws of motion. | Recites one of Kepler's laws from memory without its basis. | Uses Tycho Brahe's precise naked-eye data to justify Kepler's three laws — ellipses, equal areas, and the period–distance relation. |
| Galileo's telescope evidence | Cannot say what Galileo observed or why it mattered. | Names Jupiter's moons but not their significance. | Explains how Jupiter's moons and the phases of Venus were direct evidence against an Earth-centered universe. |
| Tracking the sky & the journal | Accepts claims on authority and leaves the observation journal blank. | Reads about the debate but keeps thin, undated notes. | Tracks a planet's position over weeks under a red flashlight, logging dated sketches, and argues from that evidence rather than authority. |
| 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 reasoning over recall: not naming Copernicus, but showing why a Sun-centered model explains the retrograde loops more simply. Ask “why did the old model seem right for so long?”
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 geocentric model & its logic | NY / Appr / Mast | |
| 2 | The shift to a heliocentric model | NY / Appr / Mast | |
| 3 | Tycho's data & Kepler's laws | NY / Appr / Mast | |
| 4 | Galileo's telescope evidence | NY / Appr / Mast | |
| 5 | Tracking the sky & 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.