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Day 5. How do igneous rocks form?. Igneous rocks form when molten rock (magma or lava) cools and hardens. How do metamorphic rocks form?. Metamorphic rocks form when an existing rock changes due to heat and/or pressure. Daily Warm-Up Exercises. Compare Rock Formation, Part 1.
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Day 5 How do igneous rocks form? Igneous rocks form when molten rock (magma or lava) cools and hardens. How do metamorphic rocks form? Metamorphic rocks form when an existing rock changes due to heat and/or pressure. Daily Warm-Up Exercises
Compare Rock Formation, Part 1 Contrasting Case Activity 2 Earth History, Investigation 8 Compare Rock Formation
Which is Which? 20 – slate Metamorphic Rock 1 – This rock forms when shale, a sedimentary rock, changes due to heat and pressure. This process happens deep beneath Earth’s surface. Before the change, shale is a smooth, hard, dull rock with very fine grains arranged in layers. After the change, the new rock is also smooth with very fine grains, but it is harder, shinier, and more compact than shale. Shale often contains fossils, but the new rock rarely does. The biggest change is that the new rock can be easily split into sheets of different thicknesses. For this reason, it is often used to make roofing tiles and paving stones. Metamorphic Rock 2 – This rock forms when slate, a metamorphic rock, changes due to extreme heat. This process happens deep beneath Earth’s surface. Before the change, slate is smooth, fairly shiny, and hard. After the change, the new rock is rough and shiny, and small pieces tend to flake off easily. The biggest change is in grain size. Slate has very fine grains. The new rock has medium to coarse crystals that are flat and arranged in layers. Fossils are rarely found in slate or in the new rock. Look at rocks 1 & 20. Read & highlight WS 9 to figure out which rock is which? 1 – schist Do you remember what rock 1 is called?
Compare Metamorphic Cases case 1 = slate (20) Use this column for information that is true about both rocks. Use this column for information that is true about one but not the other. case 2 = schist (1) Fill in the table by entering information from the paragraphs to answer each question. Compare Rock Formation
Metamorphic Rock Formation changes are caused by heat and pressure An existing rock changes due to heat and/or pressure. changes are caused by extreme heat new rock is harder, shinier, and more compact; easily splits into sheets of different thicknesses Fossils are usually destroyed. very fine grains become medium to coarse crystals that are flat and arranged in layers Compare Rock Formation
Compare Igneous & Metamorphic Look at your igneous table. Based on these two rocks, how do igneous rocks form? Igneous rocks form when molten rock cools and hardens. This process can happen slowly or quickly. Look at your metamorphic table. Based on these two rocks, how do metamorphic rocks form? Metamorphic rocks form when an existing rock changes due to heat and/or pressure. Compare Rock Formation
Compare Igneous & Metamorphic What properties result from igneous formation? Igneous rocks are usually hard. They usually have crystals, but obsidian does not have crystals. What properties result from metamorphic formation? Metamorphic rocks rarely have fossils because they are usually destroyed by the heat and/or pressure. Compare Rock Formation
Igneous and Metamorphic Rocks(Part 1, steps 1-6) Investigation 8 One Rock to Another
Rock Identification A and B Using the hand lens and the acid, complete the Rock number and Description columns. Use Resource Book pages 42-46. Steps for acid test: 1. Goggles 2. Paper towel (2 pieces) 3. 1-2 drops/reverse side 4. Dry up (max 30 sec)
Rock Identification A (#11 - 13) • pink, white, black, grey • shiny flat crystals • dense igneous intrusive 11 granite igneous • grey, black, white • dense • fine-grained 12 extrusive basalt, fine-grained • black, grey • holes of various sizes • dense igneous extrusive 13 basalt, vesicular
Rock Identification A (#16 - 19) • black, dark brown • very shiny, like glass • forms sharp edges igneous extrusive 16 obsidian igneous • grey, tan with holes • not very dense • would float in water extrusive 17 pumice • browns, reds • holes like pumice • does not float in water igneous extrusive 19 scoria
Rock Identification A (#21) igneous • mostly white, some tan • chalky, grainy 21 extrusive tuff
Rock Identification B (#1 - 15) comes from shale or mudstone metamorphic 1 • black, shiny schist comes from shale or granite metamorphic • white, tan, black with lines 14 gneiss comes from limestone metamorphic • fizzes in acid • white, crystalline 15 marble
Rock Identification B (#18 - 20) metamorphic comes from sandstone 18 • pink, crystalline quartzite metamorphic comes from shale 20 • black, hard, smooth slate
Real vs. Diagram Exercise 8.1
Relative Scale and Magnification Exercise 8.2
Relative Scale and Magnification Exercise 8.3