RockLicker · Grade 8 · Lesson 2 of 5

A Rock-Cycle Evidence Network

Build a branching process model and justify a route using a supplied geological history.

  • Grade 8
  • 60 minutes
  • Worksheet + teacher guidance
Back to Grade 8

What you will learn

Rock-cycle paths can branch and repeat. Matter is transformed or moved through processes that require energy; melting, cooling, erosion, burial and metamorphism do different jobs.

Words to use

  • process network: connected alternative paths
  • matter: material moved or changed
  • energy: what drives change

Evidence for this lesson

Supplied history: molten material cooled; exposed rock later broke down and was transported; deposited grains became cemented; burial-related heat and pressure later changed that rock without melting.

Use the supplied record as written; do not invent missing results.

Work through the activity

  1. 10 min · Build nodesWrite igneous rock, sediment, sedimentary rock, metamorphic rock and molten material. Leave room for more than one outgoing arrow.
  2. 20 min · Label pathwaysConnect nodes with process labels. Include weathering/erosion to sediment, deposition and compaction/cementation, metamorphism without melting, melting and cooling.
  3. 20 min · Apply a historyTrace the supplied route and explain each transition. Add an alternative path in which sedimentary rock is weathered again instead of becoming metamorphic.
  4. 10 min · Check the modelFind an arrow that would be wrong without an intermediate step. Discuss heat or gravity as energy context without claiming every process has the same driver.
RockLicker
GRADE 8 · LESSON 2

A Rock-Cycle Evidence Network

Draw on the printed sheet or write, type or dictate your response.
Draw on the printed sheet or write, type or dictate your response.
Draw on the printed sheet or write, type or dictate your response.
Draw on the printed sheet or write, type or dictate your response.

Responses stay in this open page only. Print before closing or changing pages; no student record is stored online.

Check your understanding

Which transition needs a molten intermediate?

Teacher & family guide · answers and assessment

Grade 8 · A Rock-Cycle Evidence Network

Learning goal: Build a branching process model and justify a route using a supplied geological history.

Expected responses

  1. Require scientifically consistent transitions, including molten material and sediment intermediates.
  2. Molten material cools to igneous; breaks/transports to sediment; deposits and cements to sedimentary; changes while solid to metamorphic.
  3. Sedimentary weathering/erosion back to sediment is one valid alternative.
  4. Melting creates molten material; subsequent cooling produces igneous rock rather than direct solid-state metamorphism.

Understanding check: Metamorphic rock melting and cooling to igneous rock. Melting creates a melt, and cooling solidifies it. Metamorphism occurs without melting.

Watch for this misconception

A rock cycle is not a fixed conveyor belt requiring all three types in the same order.

Assess the evidence

Look for the observations, calculation or explanation named in the learning goal. Accept accurate drawings and dictated responses. Use the expected responses to discuss reasoning; a correct guess without explanation is a starting point for another conversation.

Adapt and extend

Read prompts aloud, enlarge print or let a partner record the learner’s explanation. Explain how the visible record could preserve only part of a longer route.