--- title: "Quick check: sedimentary, metamorphic and the rock cycle" subtitle: "Year 8 Earth and space · The rock cycle · Lesson 5" --- # Quick check: sedimentary, metamorphic and the rock cycle **Name:** {{field-24}} **Date:** {{field-15}} **Class:** {{field-15}} > **Key question:** The same atoms have been rock, sand, mud and lava many times over. How do rocks change from one kind to another? :::teacher-note **In one sentence:** A self-test on sedimentary and metamorphic rock formation, the rock cycle and rock properties and uses (AC9S8U04, nodes 1, 3, 4 and 5, taught in class; node 4 a hinge). **Students should be able to say:** I can put sedimentary rock formation in order. I can say how metamorphic rock forms and give a parent and its product. I can trace a rock-cycle pathway and say how plate tectonics drives it. I can link a rock property to its use. **Width:** the unmarked parts are the floor every student does (Engage, Explore, Explain, Evaluate). Typical and Wider sections add contexts, not difficulty. Students work in the online tutorial alongside this sheet. ::: ## Sedimentary rocks :::keep-together ### The sequence **Which is the correct order for forming a sedimentary rock?** ☐ Erosion, lithification, weathering, deposition ☐ Deposition, weathering, lithification, erosion ☐ Weathering, erosion and transport, deposition, lithification ☐ Lithification, deposition, weathering, erosion ::: :::teacher-note **Answer:** Weathering, erosion and transport, deposition, lithification Rock is broken down (weathering), carried away (erosion and transport), settles in layers (deposition), then is squashed and cemented into rock (lithification). ::: :::keep-together ### Layers and fossils **Why are fossils found in sedimentary rock but hardly ever in igneous rock?** ☐ Only sedimentary rock is old enough ☐ Igneous rock is too soft ☐ Sediment gently buries dead organisms and preserves them, while molten rock would destroy them ☐ Fossils are made by volcanoes ::: :::teacher-note **Answer:** Sediment gently buries dead organisms and preserves them, while molten rock would destroy them Dead organisms can be buried in mud or sand and turn into fossils as the sediment becomes rock. Molten rock would burn them. ::: :::keep-together ### Properties and formation **Which sedimentary property comes from which step?** Groups: Deposition, Lithification - Visible layers (strata): {{field-15}} - Grains stuck together by cement: {{field-15}} - Sorted grains of similar size: {{field-15}} - Hardened, compacted rock: {{field-15}} ::: :::teacher-note **Answer:** Visible layers (strata) → Deposition; Grains stuck together by cement → Lithification; Sorted grains of similar size → Deposition; Hardened, compacted rock → Lithification ::: ## Metamorphic rocks :::keep-together ### How they form **How does a metamorphic rock form?** ☐ Rock is worn down by wind ☐ Rock melts and then cools ☐ Sediment settles in layers ☐ Existing rock is changed by heat and pressure without melting ::: :::teacher-note **Answer:** Existing rock is changed by heat and pressure without melting If the rock melted it would become magma and form an igneous rock. Metamorphic rocks change while solid. ::: :::keep-together ### Banding **Many metamorphic rocks, such as gneiss, show bands. Why?** ☐ They contain fossils ☐ They were deposited in layers ☐ Pressure in one direction squashes and lines up the minerals ☐ They cooled quickly ::: :::teacher-note **Answer:** Pressure in one direction squashes and lines up the minerals Squeezing from one direction flattens and aligns the minerals into bands (foliation). ::: :::keep-together ### Parent and product **What does it become with heat and pressure?** Groups: Marble, Slate, Quartzite - Limestone: {{field-15}} - Shale (mudstone): {{field-15}} - Sandstone: {{field-15}} ::: :::teacher-note **Answer:** Limestone → Marble; Shale (mudstone) → Slate; Sandstone → Quartzite ::: ## The rock cycle :::keep-together ### A pathway **How could a sedimentary rock become an igneous rock?** ☐ It is buried deep, melts into magma, then cools and crystallises ☐ It cannot ☐ It is weathered into sediment ☐ It is squashed without melting ::: :::teacher-note **Answer:** It is buried deep, melts into magma, then cools and crystallises Any rock can melt and re-form. The cycle has no fixed start or end. ::: :::keep-together ### How long? **Which process usually takes the longest?** ☐ A flood carrying sand downstream ☐ Lava cooling into basalt ☐ Frost cracking a rock ☐ Sandstone turning into quartzite deep underground ::: :::teacher-note **Answer:** Sandstone turning into quartzite deep underground Surface processes are usually quick (hours to years). Burial, heating and pressure deep down take thousands to millions of years. ::: :::keep-together ### What drives it **How does plate tectonics keep the rock cycle going?** ☐ It only affects the oceans ☐ It buries rocks to where they melt or change, and lifts others up to be weathered ☐ It stops rocks from melting ☐ It makes rocks magnetic ::: :::teacher-note **Answer:** It buries rocks to where they melt or change, and lifts others up to be weathered Subduction carries rock down to heat and pressure; collisions lift rock into mountains where it weathers. Without movement the cycle would stall. ::: :::keep-together ### A second pathway **How could an igneous rock become a sedimentary rock?** ☐ It melts and cools again ☐ It is weathered and eroded into sediment, which is deposited in layers and lithified ☐ It is heated and squashed without melting ☐ It can't: igneous rock is too hard to change ::: :::teacher-note **Answer:** It is weathered and eroded into sediment, which is deposited in layers and lithified At the surface, weathering breaks any rock into sediment. That is a second pathway round the cycle. ::: ## Properties and uses :::keep-together ### A benchtop **Granite is used for kitchen benchtops. Why is it suitable?** ☐ Its minerals, mainly quartz and feldspar, are hard, and slow cooling locked them into large interlocking crystals ☐ It is made of layers ☐ It is soft and easy to cut ☐ It cooled quickly, so it has no crystals ::: :::teacher-note **Answer:** Its minerals, mainly quartz and feldspar, are hard, and slow cooling locked them into large interlocking crystals Granite's hard minerals resist scratching, and the tightly locked crystals make it strong and durable. Both come from how it formed: slow cooling of magma deep underground. ::: :::keep-together ### Marble outdoors **Marble is used for statues but wears away faster outdoors in acid rain. Why?** ☐ Rain wears every rock away at the same rate ☐ Marble is a soft sedimentary rock ☐ Marble is made of calcium carbonate, which reacts with acid ☐ Marble is full of holes that let water in ::: :::teacher-note **Answer:** Marble is made of calcium carbonate, which reacts with acid Marble forms from limestone, which is calcium carbonate. Acid slowly dissolves it, so details blur over time. ::: :::keep-together ### Choosing stone **For thousands of years Wurundjeri people quarried greenstone at Wil-im-ee Moor-ring (Mount William, Victoria) to make axe heads, which were traded across south-eastern Australia. Why choose that stone?** ☐ Its green colour made it easy to find ☐ It is hard and tough, with fine, tightly locked grains, so a ground edge stays sharp and doesn't shatter ☐ It is soft, so it is quick to shape ☐ Any nearby stone would have worked as well ::: :::teacher-note **Answer:** It is hard and tough, with fine, tightly locked grains, so a ground edge stays sharp and doesn't shatter Choosing this stone and trading it widely shows detailed knowledge of rock properties. Its fine, interlocking grains come from how it formed, and they are what make it tough. ::: ## Exit ticket :::keep-together **Name one rock type, how it forms, and one use that depends on its properties.** {{lines-3}} ::: :::teacher-note **Answer:** For example granite: cools slowly underground, hard interlocking crystals, benchtops. :::