01 / Teaching guide · Geology · 35 minutes

How a wall becomes a wonder

What changes the rock, and what carries the pieces away?

Suggested ages 10–14. Ages and timings are editorial suggestions; adapt to your learners.

Prepare & connect

Allow five minutes to read both plates. Bring paper and a pencil; a shared screen is optional. Introduce fracture (a break), weathering (breakdown) and erosion (transport). No rock collection or physical freezing experiment is required.

Optional local resource: Weathering Lab. JavaScript for controls; use Reading the model or this bundle without it.

  1. 5 minNotice before namingShow the summary plate. Ask pairs to describe shapes and gaps using only what is drawn. Then name wall, window and pillar. Ask what the spaces between these snapshots leave unknown.
  2. 15 minMake a fair comparisonIn Weathering Lab, choose Water, frost & varied beds, then set Model steps to 36. Record the wall seed and settings. Choose Take water away without using New wall; leave the step at 36. Compare reference A with experiment B. If offline, predict a difference between the two cases on the activity plate; label it a prediction.
  3. 10 minTrace the materialFor each change, ask whether rock broke down or moved. Draw an arrow only where your explanation involves transport. Describe how a window could lose its span without claiming that every wall follows this exact path.
  4. 5 minExit claimComplete: In this model, changing ___ affected ___. This does not tell us ___. Use a control or a specific part of a plate as evidence.
Listen for

Look for a controlled comparison and an explicit separation of breakdown from transport. A drawing alone cannot establish speed or predict the future of a named hoodoo. Accept ‘not tested’ when the interactive resource is unavailable.

Access: Read the plate descriptions aloud; learners may dictate a claim or point to a numbered stage. All meaning is also written outside the diagram.

BCC Educator Collection · 01 · Teaching guide · 1 of 3 · October 2026 · Independent educational draft; no NPS affiliation or curriculum certification.

01 / Read the evidence · Learner sheet

How a wall becomes a wonder

Water, fractures and differences in rock resistance help shape the landscape. Weathering changes or breaks rock in place; erosion moves material. Fins, windows and isolated pillars provide a useful conceptual sequence. The summary plate is an original diagram, not observations of one rock through time.

01 / Read the evidenceWall → window → pillars: three explanatory shapes, with no duration or scale assigned. 01 / Read the evidenceBCC Educator Collection · Compare causes 1 · Wall2 · Window3 · Pillars Original illustration · no measured scale
Wall → window → pillars: three explanatory shapes, with no duration or scale assigned.

Look closely

  1. Where can you point to a change in the shape? Where would removed material need to go?
  2. Which control did you change? Which settings and comparison step stayed the same?
  3. What evidence would you need before converting model steps to years?

Evidence limit: Illustrative rules and invented geometry; no erosion rate, weather forecast, measured hoodoo history or ground-level scan.

Reading behind the lesson

BCC Educator Collection · 01 · Read the evidence · 2 of 3 · October 2026 · Independent educational draft; no NPS affiliation or curriculum certification.

01 / Try the question · Learner sheet

Compare causes

Use the two-case frame to design a comparison. Name one changed variable, two controls and an observable outcome. Write a prediction before using the model, then compare it with the result. Keep the offline prediction distinct from a result you actually observed.

01 / Try the questionTwo hypothetical wall experiments. Water is the proposed changed variable; time step, wall and other controls must match. 01 / Try the questionBCC Educator Collection · Compare causes Case A · waterSame wall + same stepCase B · no waterSame wall + same step Original illustration · no measured scale
Two hypothetical wall experiments. Water is the proposed changed variable; time step, wall and other controls must match.
Our changed variable / held-steady settings:
Prediction, then model observation (or ‘not tested’):
Our claim and one thing this evidence cannot establish:

Take it further: Compare equal resistance with varied resistance while holding water and fracture spacing steady. Does your first explanation still account for the shapes?

Success looks like: Write a claim that stays within the evidence of a simulation.

All lessons and plates are included in this local copy. Linked experiences are optional. No learner names, responses or locations are collected by this collection.

Save summary plate (SVG) · Save activity plate (SVG)

BCC Educator Collection · 01 · Try the question · 3 of 3 · October 2026 · Independent educational draft; no NPS affiliation or curriculum certification.