Use a branching process key
The original practice model begins with igneous rock. It offers these simplified routes:
| Starting material | Supplied process | Result in this model | Explanation to check |
|---|---|---|---|
| Igneous rock | Solid-state metamorphism through suitable heat and/or pressure | Metamorphic rock | The rock changes while remaining solid. |
| Igneous rock | Weathering, transport, and deposition | Sediment | Broken-down material is moved and deposited; it is not yet a sedimentary rock. |
| Sediment | Compaction and cementation | Sedimentary rock | The deposited material becomes rock. |
| Igneous, sedimentary, or metamorphic rock | Melting | Magma | Melting creates molten material, not metamorphic rock. |
| Magma | Cooling and crystallization | Igneous rock | The molten material forms rock as it cools. |
The Lunar and Planetary Institute rock-cycle resource explains formation processes and warns against a compulsory one-way sequence or partly melted metamorphic rock. The table is an original limited teaching model. It does not identify a real sample or calculate the conditions and time needed for a transformation.
Make each choice leave a readable history
A learner choosing solid-state metamorphism should see Igneous rock → solid-state metamorphism → metamorphic rock. Choosing the sediment route should record each distinct stage, including sediment before sedimentary rock.
For the melt-and-cool route, retain Igneous rock → melting → magma → cooling and crystallization → igneous rock. Returning to an igneous label does not mean nothing happened; the history shows the processes that produced the new rock.
Ask learners to explain one arrow in their chosen path. “It is next in the circle” does not justify the change. “The rock remained solid while changing under suitable conditions” distinguishes metamorphism from melting.
Give an invalid choice useful feedback
Do not offer every process as equally applicable to every current material. If a learner tries to turn sediment into magma without a melting step, retain the current state and point to the missing transformation. If they say melting makes metamorphic rock, explain the solid/molten distinction directly.
In this model, provide cooling for magma and compaction/cementation for sediment. Keep the transition table available to the teacher so a diagram and a text history cannot disagree. Avoid an animation that appears to show real temperatures, depths, or geological rates the task has not supplied.
Undo should return both the current material and history to the preceding step. Reset should return to the supplied starting rock and clear the chosen path and feedback. A blank path means no process has been chosen, not that the learner has failed the exercise.
Prompt for a process-path worksheet
Draft an original rock-cycle pathway exercise in US English.
Learners and model scope: [inputs]
Source-supported starting materials and allowed transitions: [paste key]
Processes to contrast: [inputs]
Required school format: [format]
Give a branching transition table with starting material, process, resulting material, and explanation. Include solid-state metamorphism, a weathering/transport/deposition-to-sediment route followed by sedimentary formation, and melting-to-magma followed by cooling-to-igneous where supported by my key. Do not force one circular sequence or call metamorphic rock partly melted. Preserve intermediate states.
Describe keyboard-accessible process choices, full text path history, explanatory check, undo, and reset. Invalid choices must not change the current material. Undo restores both material and history; reset restores the original start and clears feedback. Give a full text alternative to the diagram and no color-only paths. Do not claim this unbuilt exercise is a tested simulation.
Do not invent sample identification, thermal thresholds, ages, measurements, learner results, or standards. Mark unsupported transitions [TEACHER TO CONFIRM] and missing inputs [NEEDED: input]. Return learner task and teacher key in the requested format with official assessment records separate.
Trace two routes before class
If the prepared path sheet is HTML, NOS can save and render it while you review each process and result. Keep actual learner observations in the school record. Trace a solid-state route and a melt-and-cool route, then confirm that their explanations differ for the scientific reason the worksheet is meant to teach.