The rock cycle explains how Earth materials change from one rock type to another over long periods of time. In this project, students build an interactive model wheel using colored clay, candy, or craft materials to represent igneous, sedimentary, and metamorphic rocks. The model matters because it turns an invisible geologic process into something students can touch, move, label, and explain.
A good model shows both the rock types and the forces that transform them.
Key Facts
- Melted rock that cools and hardens = igneous rock.
- Sediments + compaction + cementation = sedimentary rock.
- Existing rock + heat + pressure = metamorphic rock.
- Weathering breaks rock into smaller pieces, and erosion moves those pieces.
- Melting turns rock into magma, and cooling turns magma or lava into igneous rock.
- The rock cycle has no single starting point because any rock type can change into another over time.
Vocabulary
- Igneous rock
- Rock formed when magma or lava cools and hardens.
- Sedimentary rock
- Rock formed from layers of sediment that are compacted and cemented together.
- Metamorphic rock
- Rock formed when existing rock is changed by heat and pressure without completely melting.
- Weathering
- The process that breaks rock into smaller pieces by water, wind, ice, temperature change, or living things.
- Magma
- Hot melted rock found beneath Earth's surface.
Common Mistakes to Avoid
- Showing the rock cycle as one simple circle, because rocks can move through many different pathways instead of always following the same order.
- Confusing melting with metamorphism, because metamorphic rock changes under heat and pressure but does not fully melt.
- Leaving out erosion after weathering, because broken sediment must also be moved before it can collect in layers.
- Labeling candy or clay pieces only by color, because the model should connect each material choice to a real rock feature such as layers, crystals, or banding.
Practice Questions
- 1 A model wheel has 3 main rock type sections. If each section takes up the same amount of space on a 360 degree circle, how many degrees should each section cover?
- 2 A student uses 24 clay pieces for sediments and wants to make 6 equal sedimentary layers. How many clay pieces should be in each layer?
- 3 In your model, a piece of sedimentary rock is buried deeper underground and exposed to strong heat and pressure, but it does not melt. Explain what type of rock it becomes and why.