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.
Student lessons, data, and worked answers: Unit 08 learning pathway.
The student demonstrates the following:
Five science criteria plus separately reported integration (Page 3).
Model decay across half-lives; compute an age from the ratio.
The student reads Earth history on the geologic time scale (Page 4).
Decay curve, parent/daughter ratio, and age 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 age calculation is defensible and the student can place the events on the geologic time scale. 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 |
|---|---|---|
| Ordering time | ||
| Superposition | law of superposition | In undisturbed layers the oldest is on the bottom |
| Cross-cutting relationships | cross-cutting | A fault or intrusion is younger than the rock it cuts |
| Unconformity | erosional gap | A buried surface — missing time in the record |
| Relative dating | ordering without numbers | Places events in sequence, not in years |
| Dating & the time scale | ||
| Radiometric dating | numerical event dating | Requires material/system context; crystallization need not date sediment deposition |
| Half-life | decay half-time | Time for half the parent isotope to decay to daughter |
| Closed-system / initial daughter | clock-model conditions | Retention and initial composition must be addressed; the toy clock is not every real dating system |
| Geologic time scale | eons / eras / periods | The calendar of Earth history — origin of life to now |
| Deep time | Hutton’s deep time | Earth’s vast age — “no vestige of a beginning, no prospect of an end” |
| Criterion | Developing | Proficient | Mastery |
|---|---|---|---|
| Relative dating principles | Cannot order rock layers or events. | Names superposition but misapplies cross-cutting or inclusions. | Orders events using superposition, cross-cutting relationships, and inclusions, and reads an unconformity as missing time. |
| Radiometric dating & half-life | Cannot connect a ratio to a stated clock model. | Computes an age but ignores initial daughter or system history. | Uses the assigned decay model and assumptions, identifying the material and event dated rather than equating every mineral age with deposition. |
| The geologic time scale | Cannot place major events in order. | Names eras but not their sequence or defining events. | Places major events — the origin of life, mass extinctions, key evolutionary steps — within their eons, eras, and periods. |
| Deep time & Earth history | Thinks Earth’s past fits human timescales. | Repeats “deep time” but cannot reason at its scale. | Uses Hutton’s deep time to interpret slow processes and mass extinctions across the full sweep of Earth history. |
| Decay simulation & dated-event interpretation | Misreads the model or invents missing chronological evidence. | Calculates dates but combines inconsistent events uncritically. | Plots/interprets a decay simulation, brackets events with context, and investigates inconsistent dates instead of averaging away conflicts. |
| 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 a defensible number: a student who turns a parent/daughter ratio into years and shows the decay curve has it. Ask “how many half-lives have passed, and how do you know?”
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 | Relative dating principles | Dev / Prof / Mast | |
| 2 | Radiometric dating & half-life | Dev / Prof / Mast | |
| 3 | The geologic time scale | Dev / Prof / Mast | |
| 4 | Deep time & Earth history | Dev / Prof / Mast | |
| 5 | Decay simulation & dated-event interpretation | 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.