Use these targets, vocabulary, rubrics, examples, and score sheet with the instructor's approved lesson and procedure. This is an assessment companion, not a complete lesson or safety authorization.
By the end of the Torque & Rotational Motion unit, a student should be able to:
Five science criteria plus separately reported integration (Page 3).
Predict a balance point; verify it on a meter stick.
The student explains why a skater spins faster with arms in (Page 4).
Distances, torque balance, and result kept distinct.
You are making a decision, not adding up points. For each criterion, decide whether the work is Developing, Proficient, or Mastery — the column language tells you which. A criterion counts as mastered only when the student can both predict the balance and defend it from the torques. Each student has three tokens per term; each token retries one rubric criterion. Approved accommodations, equipment failures, and approved absences are handled separately and do not consume these tokens.
Accept listed synonyms; use the distinction column to resolve near-matches.
| Canonical answer | Accepted synonyms | Common confusion / discriminator |
|---|---|---|
| Torque & balance | ||
| Torque | moment of force | Force times lever arm — where the force acts matters, not just its size |
| Lever arm | moment arm | The perpendicular distance from the pivot to the line of force |
| Pivot | fulcrum / axis | The axis you take torques about; choose it to simplify the problem |
| Rotational equilibrium | balanced torques | Net torque and net force both zero — neither spins up nor accelerates |
| Rotation | ||
| Rotational inertia | moment of inertia | Depends on how mass is distributed, not just how much |
| Angular momentum | spin momentum | Conserved when no external torque acts; pull mass in and spin rises |
| Angular velocity | spin rate | How fast it turns; increases as rotational inertia decreases |
| Center of mass | balance point | The point where weight effectively acts |
| Criterion | Developing | Proficient | Mastery |
|---|---|---|---|
| Torque | Thinks only the size of the force matters, not where it acts. | Uses force times distance but ignores the angle or lever arm. | Calculates torque as force times lever arm, accounts for direction, and explains why a longer wrench is easier. |
| Rotational equilibrium | Cannot set up a balance condition. | Balances torques but forgets to also balance forces. | Solves static-equilibrium problems by setting net torque and net force to zero about a chosen pivot. |
| Rotational inertia | Thinks only total mass matters, not its arrangement. | Knows shape matters but cannot compare two objects. | Explains that rotational inertia depends on how mass is distributed and ranks objects that roll or spin accordingly. |
| Angular momentum | Does not recognize a rotational analog to momentum. | Names angular momentum but cannot apply conservation. | Applies conservation of angular momentum to explain spin-up and spin-down when the radius changes. |
| Lab technique (balance / rotational inertia) | Balances by trial and error with no measurement. | Measures distances but does not predict the balance point first. | Uses a meter-stick balance to predict and then verify equilibrium, reporting the result with uncertainty. |
| Integration (cross-domain) | Makes no supported connection between the source and the science. | Uses the source but needs help connecting evidence, writing, or limitations to the science. | Independently connects History, Reading, and Writing using a cited source, appropriate evidence, a limitation, and a scientific explanation. |
The split between Proficient and Mastery is lever arm: a mastered student weighs distance as much as force. Ask “a small mass far out balances a big mass close in — why?”
Read these before you grade. They show what Mastery and Developing actually sound like, plus the edge cases where you should coach rather than decide on the spot.
Student: ______________________________________ Date: _______________ Guide: _________________________
| # | Criterion | Decision | Notes |
|---|---|---|---|
| 1 | Torque | Dev / Prof / Mast | |
| 2 | Rotational equilibrium | Dev / Prof / Mast | |
| 3 | Rotational inertia | Dev / Prof / Mast | |
| 4 | Angular momentum | Dev / Prof / Mast | |
| 5 | Lab technique (balance / rotational inertia) | Dev / Prof / Mast | |
| 6 | Integration (cross-domain) | Dev / Prof / Mast |
☐ No ☐ Yes — for criterion: __________
Tokens left this term after this session (choose one): ☐ 3 ☐ 2 ☐ 1 ☐ None left
Dev = Developing · Prof = Proficient · Mast = Mastery · Unsure between two levels? Circle the lower one and note what a re-do would need.