This packet is everything a parent or guide needs to assess Unit 07 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 modeling cosmic expansion by hand and reasoning from the cosmic microwave background.
By the end of the Cosmology & the Big Bang unit, a student should be able to:
Six criteria, each judged Not yet / Approaching / Mastered (Page 3).
Inflate a balloon or bake raisin bread to show every point receding.
The student corrects the “explosion in space” picture (Page 4).
Model results, CMB reasoning, and the age estimate kept distinct.
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 correct the “explosion in space” picture and defend the evidence for an expanding universe. A student carries three tokens per term; one token buys a re-do of one criterion on another day, so a single rough afternoon 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 |
|---|---|---|
| Expansion & the Big Bang | ||
| Hubble's law | recession–distance relation | Farther galaxies recede faster; space itself stretches |
| Expansion of space | metric expansion | Space stretches between galaxies — not galaxies flying through fixed space |
| No center, no edge | the “explosion” correction | The Big Bang happened everywhere at once, not at one point |
| Redshift | cosmological redshift | Stretched light from receding galaxies; grows with distance |
| Evidence, age & fate | ||
| Cosmic microwave background | CMB; relic afterglow | Cooled glow of a hot, dense early universe — the key evidence |
| Age of the universe | ~13.8 billion years | Found by running the expansion rate backward |
| Dark energy | accelerating expansion | Unknown cause speeding up expansion; shapes the universe's fate |
| Balloon / raisin-bread model | expansion analogy | Every point recedes from every other; the surface has no center |
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Hubble's law & expanding space | Thinks galaxies fly through a fixed, static space. | Says the universe expands but not that space itself stretches. | States Hubble's law and explains that space itself expands, carrying galaxies apart. |
| Correcting the “explosion” picture | Pictures the Big Bang as a bomb going off at one point. | Senses the picture is wrong but cannot say why. | Corrects the misconception — the Big Bang was the expansion of space everywhere, not an explosion into pre-existing space. |
| The cosmic microwave background | Knows no evidence for the Big Bang. | Names the CMB but not what it shows. | Explains the cosmic microwave background as the cooled afterglow that evidences a hot, dense early universe. |
| Age of the universe & its fate | Has no sense of the universe's age. | Gives a number but cannot say how it is found. | Estimates the age from the expansion rate and describes dark energy and the possible fates it implies. |
| Modeling cosmic expansion | Cannot demonstrate expansion or insists there is a center. | Inflates a balloon model but calls its starting point the center. | Uses a balloon or raisin-bread model to show every point receding from every other — no center, no edge. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
The split between Approaching and Mastered is space itself expands: galaxies are not flying through space from a blast site — the space between them stretches. Ask “where was the center of the Big Bang?” The mastered answer is that there isn't one.
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 | Hubble's law & expanding space | NY / Appr / Mast | |
| 2 | Correcting the “explosion” picture | NY / Appr / Mast | |
| 3 | The cosmic microwave background | NY / Appr / Mast | |
| 4 | Age of the universe & its fate | NY / Appr / Mast | |
| 5 | Modeling cosmic expansion | 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.