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 comparing marks on the comparison microscope and reconstructing a trajectory from the geometry.
By the end of the Ballistics & Toolmarks unit, a student should be able to:
Six criteria, each judged Not yet / Approaching / Mastered (Page 3).
Align striations on the comparison microscope; reconstruct a trajectory.
The student reports consistency and confidence, not certainty (Page 4).
Comparison, degree of agreement, and confidence 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 compare the marks and report confidence, not certainty. A student carries three tokens per term; one token buys a re-do of one criterion on another day, so a single bad 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 |
|---|---|---|
| Marks & comparison | ||
| Rifling | lands & grooves | Spiral grooves cut in a barrel; they scratch striations onto a fired bullet |
| Striations | striae | Fine parallel scratches; the pattern an examiner aligns and compares |
| Comparison microscope | dual-stage comparison scope | Views two specimens side by side to align striations |
| Toolmark | tool impression | A mark a tool leaves on a surface; compared for consistency, not certainty |
| Characteristics & scene | ||
| Class characteristics | shared-feature marks | Features shared by a whole group (caliber, tool type); narrow, do not individualize |
| Individual characteristics | unique wear marks | Fine, chance features from wear; the basis for a stronger comparison |
| Trajectory | flight path | The path a projectile traveled; constrained by angle, distance, and geometry |
| Angle of impact | impact angle | The angle at which a projectile struck; used to reconstruct the path |
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Firearm & cartridge basics | Cannot say how a fired cartridge picks up marks. | Names parts but not how firing and extraction leave marks. | Explains how a firearm and cartridge produce the marks an examiner later compares. |
| Rifling & striation comparison | Cannot use the comparison microscope to align striations. | Aligns marks but reads agreement inconsistently. | Compares rifling striations on the comparison microscope and describes the degree of agreement it shows. |
| Toolmark comparison & its limits | Declares a toolmark a certain match. | Compares marks but overstates the strength of the finding. | Compares toolmarks and reports consistency and a level of confidence, explaining why an examiner does not claim certainty. |
| Trajectory & the physics of the scene | Ignores angle, distance, or geometry at the scene. | Estimates a path but cannot justify it from the geometry. | Uses angles, distance, and geometry to constrain a trajectory, stating the uncertainty in the reconstruction. |
| Technique & documentation | Handles or records evidence without a clear method. | Documents unevenly or leaves gaps in the record. | Handles evidence with consistent technique and documents each comparison so another examiner could follow it. |
| 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 confidence, not certainty: a good examiner reports how well the marks agree and how sure that makes them — never “a certain match.” Ask “how consistent are the marks, and how confident are you?”
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 | Firearm & cartridge basics | NY / Appr / Mast | |
| 2 | Rifling & striation comparison | NY / Appr / Mast | |
| 3 | Toolmark comparison & its limits | NY / Appr / Mast | |
| 4 | Trajectory & the physics of the scene | NY / Appr / Mast | |
| 5 | Technique & documentation | 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.