The demonstration-moment script.

The demonstration is the part of the course that cannot be faked, outsourced, or generated. A student stands in front of you and shows understanding in real time, against a rubric, out loud. Your job is to run it the same way every time: a setup that makes faking impossible, a question ladder that probes past rehearsal, and a clean binary verdict recorded against the rubric.

The three rules that govern every demonstration

1. The student does the work; you only ask. No coaching, no leading questions, no "are you sure?" that signals the answer. You probe understanding — you never supply it.
2. The verdict is binary. Mastery or not yet. You are not assigning a score in the room; you are deciding whether the published rubric's bar was cleared.
3. A "not yet" is a checkpoint, not a failure. How you deliver it determines whether the student comes back. Name the specific gap, give the re-attempt path, and keep the door open.

Demonstration 1 — The rock & mineral ID defense

Scored against the rock & mineral ID defense rubric · after Unit 04.

Setup. The student identifies unknown specimens on their own bench — their streak plate, their Mohs hardness kit, their hand lens for luster and cleavage-versus-fracture, and the dilute-acid dropper for the carbonate test. You hand over the specimens; they run each test, read the results, and reason to an identification out loud against a dichotomous key while you watch their hands and listen to their reasoning. Judge the observed work and explanation together; do not infer independent understanding from a finished result alone.

The question ladder:

• Procedure: "Run your tests on this specimen and give me the identification." (Can they get clean, defensible observations — streak, hardness, luster, cleavage or fracture, acid reaction?)
• Reasoning: "Walk the dichotomous key with me — which property split the call?" (Do they reason from the diagnostic properties, not a memorized specimen list?)
• System: "Why does the streak plate, or the hardness kit, discriminate here?" (Do they understand what each test actually measures?)
• Counterfactual: "If this specimen fizzed in dilute acid but you'd called it a silicate, what changes and why?" (This asks the student to apply the idea to a changed situation.)

Demonstration 2 — Timed map & cross-section reading

Scored against the timed map & cross-section rubric · after Unit 06.

Setup. Under a time limit, the student interprets a geologic map, a cross-section, and a seismogram trace — reading the structures, ordering the events, and telling the story the rock record holds. Follow the published timing and any approved accommodations. A time limit does not establish independent work by itself; observe the technique and ask the student to explain the result.

The question ladder:

• Read & observe: "Read the map and tell me exactly what you see." (The interpretive skill itself — units, contacts, folds, faults, dip directions.)
• Interpret: "What's the order of events, and which relationship told you?" (Can they apply superposition, cross-cutting relationships, and unconformities from the evidence in front of them, not from memory of a worked example?)
• Discriminate: "How do you know this contact is a fault and not a depositional boundary?" (The recurring confusion pair — use the answer to identify the specific misconception.)

Demonstration 3 — Oral lab-notebook defense

Scored against the lab-notebook-defense rubric · end of each unit.

Setup. The student walks you through their own notebook: the question, the method, the data, the anomalies, the interpretation. Ask the student to connect the explanation to specific entries. Record what the evidence supports and what needs further checking.

The question ladder:

• Narrate: "Walk me through what you did and why." (Does the story hold together?)
• Anomaly: "This data point doesn't fit — what happened?" (Did they notice, and can they reason about it honestly rather than hide it?)
• Method critique: "What would you change if you ran it again?" (Do they understand the method's limits and sources of error?)
• Transfer: "How does this connect to the concept from this unit?" (Integration — scored on its own line.)

Reading the room: Mastery vs. Proficient

Recording the verdict

Mark the rubric in the room while it's fresh — pass or not-yet on each rubric line, with a one-line note on the deciding moment. If the verdict is "not yet," that note becomes the re-attempt instruction. Do not soften the rubric to avoid an awkward conversation; soften the delivery instead.

Delivering a "not yet" so the re-attempt stays likely

• Lead with what was solid before naming the gap — the student needs to know the work wasn't wasted.
• Name one specific thing to close, not a list. ("The counterfactual on the hardness call — come back when you can reason through how a mis-read scratch test shifts the identification.")
• Give the date and the path. A "not yet" with a re-attempt slot on the calendar is a checkpoint; a "not yet" with no path is a wall.