(Test Bank) Laboratory Manual in Physical Geology

Cronin,Tasa, 10

Geography, Geology & Earth Science

Test Bank

10th Edition

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Test Bank for Laboratory Manual in Physical Geology, The downloadable file consists of 164 pages, and the total size of the file is 7.75 MB. Purchase now only for highly discounted price.

Author(s): Cronin, Tasa

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© 2015 Pearson Education, Inc. 1 Table of Contents General Tips for Getting Started 2 Errata 4 Before You Teach a Laboratory 5 Pedagogical Model 7 Lab 1: Thinking Like a Geologist 8 Lab 2: Plate Tectonics and the Origin of Magma 23 Lab 3: Mineral Properties, Identification, and Uses 40 Lab 4: Rock -Forming Processes and the Rock Cycle 48 Lab 5: Igneous Rocks and Processes 54 Lab 6: Sedimentary Processes, Rocks, and Environments 61 Lab 7: Metam orphic Rocks, Processes, and Resources 72 Lab 8: Dating of Rocks, Fossils, and Geologic Events 77 Lab 9: Topographic Maps and Orthoimages 87 Lab 10: Geologic Structures , Maps, and Block Diagrams 99 Lab 11: Stream Processes, Lan dscapes, Mass Wastage, and Floo d Hazards 1 16 Lab 12: Groundwater Processes, Resources, and Risks 127 Lab 13: Glaciers and the Dyn amic Cryosphere 137 Lab 14: Dryland Landforms, Hazards, and Risks 146 Lab 15: Coastal Processes, Landforms, H azards, and Risks 154 Lab 16: Earthquake Hazards and Human Risks 159 2 © 2015 Pearson Education, Inc. GENERAL TIPS FOR GETTING STARTED Please consider these tips to help you use the Laboratory Manual in Phy sical Geology — AGI/NAGT (10th edition) and this Instructor Manual more effectively. 1. Review the lab manual Instructor Resource Materials that are available to you, and obtain the ones you need. You can find these resources online at www.pearsonhighered.c om/irc or you can contact your Pearson -Prentice Hall sales representative at www.pearsonhighered.com/educator/replocator/ 2. Review the Pedagogical Model upon which the lab manual is based (page 6). 3. Familiarize yourself with the following resource ma terials that are available to your students : Pre-lab Videos created by Callan Bentley help students understand how to successfully complete the lab activities by following a clear series of steps. They can be accessed with the QR code on the cover flap of the lab manual or at mygeoscienceplace.com GeoTools are cardboard and transparent rulers, protractors, grain size scales, UTM grids, and more for students to cut out and use as needed. They can be found at the end of the lab manual. A Math Conversion Char t, Introduction to SI Units, pictures of lab equipment, and a map of North America are available in the Preface of the lab manual (pages xi –xiv). TMYNTM, Ma steringGeologyTM, and Learning CatalyticsTM, if used. QR Codes, which provide students with quick a ccess to web sites they need or may use in addition to resources provided in the lab manual. 4. Consider personalizing your students’ learning experience by using MasteringGeologyTM, Learning CatalyticsTM, or TMYN (The Math You Need, When You Need It) rem edial tutorials. MasteringGeologyTM is an online tutorial and homework program . Pre-lab video quizzes can be assigned as formative assessments for you to analyze with a variety of tools to isolate weaknesses and misconceptions of a student or class. This a llows you to build a plan for intervention and make the most of the time that students will have in the laboratory. Learn more at www.MasteringGeology.com Learning CatalyticsTM is pedagogical approach in which students use any web - enabled device of their c hoice (smart phone, tablet, laptop, etc.) to engage in formative assessments (that guide learning) and summative assessments (that are used for grading purposes) before, during, or after the laboratory. You can create or select multiple choice questions fo r students to answer a nd/or you can create or select open - ended questions th at ask for numerical, written, or graphical responses . You can build a seating chart, and then use the chart to see what students or groups of students have answered specific items and how they answered them. You can assign questions for students to answer synchronously during class/lab (one question is answered by each student, but all students address the question at the same time), or in a self -paced © 2015 Pearson Education, Inc. 3 mode for formative or summati ve assessments. Learn more at learningcatalytics.com/ TMYNTM is an online set of modular math tutorials for students in any introductory geoscience, developed and managed by Jennifer Wenner (University of Washington –Oshkosh) and Eric Ba er (Highline Communi ty College) with funding from the National Science Foundation. You can assign the free modules for students to use on their own, or you can assign them as formative or summative assessments. You can also compare students’ pre -lab and post -lab ability to so lve geological problems involving mathematics and, thereby, measure the extent of their learning. Learn more at serc.carleton.edu/mathyouneed/index.html Please send comments, criticisms, and suggestions regarding the laboratory manual or this instr uctor manual directly to Rich Busch, Department of Geology and Astronomy, West Chester University, West Chester, PA 19383 or rbusch@wcupa.edu. Thank you! 4 © 2015 Pearson Education, Inc. ERRATA Lab 2 On page 58, part ―B‖ (Reflect and Discuss) is actually part ―D .‖ On pag e 68, part A, item 5b, the vector motions should be in mm/yr (not cm/yr). Lab 5 On page 136, Figure 5.4, Step 3: for the description of pegmatitic texture, change ―1 mm‖ to ―1 cm.‖ On page 144, part A, change ―Minerals Database (pages 000 – 000)‖ to ―Minerals Database (Pages 93 –97).‖ On page 152, part C, change ―200 million years ago‖ to ―190 million years ago .‖ Lab 6 On page 185, part B, change ―Photograph A‖ to Photograph B .‖ © 2015 Pearson Education, Inc. 5 BEFORE YOU TEACH A LABORATORY BEFORE LAB BEGINS 1. Decide what activities your students should complete before and during the lab. Most labs deliberately include more activities than your students could complete in a single lab period, so you can choose the activities that you think will best enable your students to learn what you expect them to learn in the lab time available. 2. Check the list of errata (page 4 in this Instructor Manual) for corrections that must be made in the lab that you plan to use. 3. Assign pre -lab preparations for your students to complete. This may include: a. Complete the first activity of the lab and by the start of the lab. b. Watch the pre -lab video for the lab. c. Take a pre -lab quiz using MasteringGeologyTM or other quiz of your design. d. Complete assigned readings in th e lab manual, class textbook, or other. e. Know wha t activities must be completed by the end of the lab period. f. Know what materials each student must bring to the start of the lab (as noted in the blue boxes of the lab manual that start of each activ ity and as noted at the start of each laboratory section of this Instructor Manual). 4. Review and assemble the Instructor Materials that you must provide during the lab period. A list of the Instructor Materials is provided in this instructor manual, at the start of each for each lab section . They are generic lists only and must be modified by you to avoid confusion and know exactly what to assemble for the laboratory. 5. Review each activity and the Answers to Questions (provided in this instructor manual) for each activity/question that you assign to your students. Some questions have more than one right answer depending on how you have presented material f or students to read or explore. 6. Analyze pre -lab results, if you are assigned a pre -lab qui z using MasteringGeologyTM or a similar program. Use that information to isolate weaknesses and misconceptions of a student or class. Then build a plan for intervention that make s the most of the time that students will have in the laboratory. 7. Develop the scope and sequence of the teaching/le arning plan that you plan to follow during the lab period. a. What will you do at the start the lab period? For example, you may: Declare the scope and sequence of what students must do during the lab period, how t hey are expected to do/record their own work yet work and/or work in collaborative groups, and the safety practices that they must follow. Review pre -lab weaknesses and misconceptions and/or use lab PowerPoint to introduce the lab . 6 © 2015 Pearson Education, Inc. Review how and where s tudents obtain the materials they need (the materials that you are providing in the lab) . Address questions. b. What will you do during the lab period? For example, you may: Allow students to work on activities at their own pace or according to your other plan. Move about the room to be sure student s/group s have the materials they need and are on task. Address questions, use guiding questions of your own to help students scaffold from the unknown to the known (or inability to ability), and implement persona l interventions as needed (especially relative to pre -lab quiz results and special -needs). c. What will you do near/at the end of the lab period? For example, you may: Review the results of each activity (item by item or the Reflect and Discuss questions f or formative purposes (i.e., to guide learning). Have students submit their individual worksheets for s ummative assessment ( evaluation for a grade). Have students complete a graded post -lab quiz. Have students address the Think About It questions linked to the lab and/or the activities that they completed. DURING THE LAB PERIOD 8. Carry out the plan that you developed above, in parts 7a and 7b. AT/NEAR THE END OF THE LAB PERIOD 9. Carry out the plan th at you developed above, in part 7c. 10. Grade m aterials and provide grades and feedback to students in a timely fashion. 11. Reflect on any feedback about the lab that students may have volunteered and use it to inform/g uide your grading and futur e teaching. © 2015 Pearson Education, Inc. 7 PEDAGOGICAL MODEL Each lab proceeds from items 1 through 4 and involves resources and assessments. 8 © 2015 Pearson Education, Inc. LABORATORY ONE Thinking like a Geologist BIG IDEAS: Geology is the science of Earth, so geologists are Earth scientists or ―geoscientists.‖ Geologists observe, describe, and model the materials, energies, and processes of change that occur within and among Earth’s spheres over time. They apply their knowledge to understand the present state of Earth, locate and manage resources, identify and mitigate hazards, predict change, and seek wa ys to sustain the human population. THINK ABOUT IT (Key Questions) : How and why do geologists observe Earth materials at different scales (orders of magnitude)? (Activity 1.1) What materials, energies, and processes of change do geologists study? (Activ ity 1.2) How and why do geologists make models of Earth? (Activity 1.3 ) How and why do geologists measure Earth materials and graph relationships among Earth materials and processes of change? (Activity 1.4) How is the distribution of Earth materials relat ed to their density? (Activities 1.4, 1.5) STUDENT MATERIALS (Remind students to bring items you check below.) _____ laboratory manual with worksheets linked to the assigned activities _____ laboratory notebook _____ pencil with eraser _____ metric rul er (cut from GeoTools sheet 1 or 2) _____ calculator _____ blue pencil or pen (Activity 1.3 only) _____ drafting compass (Activity 1.3 only) _____ several coins (Activity 1.3 only) INSTRUCTOR MATERI ALS (Check off items you will need to provide.) ACTIV ITY 1.1: Geologic Inquiry _____ none © 2015 Pearson Education, Inc. 9 ACTIVITY 1.2: Spheres of Matter, Energy, and Change _____ none ACTIVITY 1.3 : Basketball Model of Earth’s Spheres _____ drafting compasses (one per student) _____ extra metric rulers (for students who forgot th em) _____ extra blue pencils (for students who forgot them) _____ several coins/student: pennies, nickels, quarters, dimes ACTIVITY 1.4: Measurin g and Determining Relationships _____ extra metric rulers (for students who forgot them) _____ small (10 mL) graduated cylinders (one per group of students) _____ waterproof modeling clay (at least 1 cubic cm. per student) _____ gram balance (one per group of students) _____ wash bottle or dropper bottle, filled with water (one per group) _____ paper tow els to clean up spills ACTIVITY 1.5 : Density, Gravity, and Isostasy _____ extra metric rulers (for students who forgot them) _____ gram balance _____ wood blocks about 8 cm x 10 cm x 4 cm. Do not use cubes because they float diagonally. Pieces of p ine 2 x 4 studs work well. For variety, give some groups pine and others a more dense wood like walnut (one block per group of students). _____ small bucket or plastic basin of water to float wood block (one per group of students) _____ paper towel s to clean up spills ACTIVITY 1.6 : Isostasy and Earth’s Global Topography _____ large (500 mL) graduated cylinders (one per group of students) _____ pieces of basalt and granite that will fit into the large graduated cylinders (one piece of each p er group of students) _____ gram balance _____ wash bottle filled with water or dropper (one per group) _____ paper towels to clean up spills INSTRUCTOR NOTES AND REFERENCES 1. Metric and International System of Units (SI): refer to laboratory manual page xi. 2. Mathematical conversions: refer to laboratory manual page xii. 3. In Activity 1.5 of this laboratory, students explore the isostasy of a floating wood block. You can make this more of a real -world inquiry by providing students with two or more den sities of wood. For example, pine and walnut work well because 10 © 2015 Pearson Education, Inc. students can easily see that the pine blocks float higher than the walnut blocks. This makes it easier for students to conceptualize how isostatic differences between granitic and basaltic bloc ks may explain Earth’s hypsographic curve. 4. Hydrous minerals of Earth's Mantle. Hydrous minerals include not only the obviously hydrous minerals like gypsum, but also minerals like amphibole and pyroxene that are "nominally hydrous" (actually hydrous even though they are generally regarded as anhydrous). See David R. Bell and George R. Rossman's 1992 paper on this ( Science , v. 255, p. 1391 –1397). Shortly after the Science article was published, Science News quoted Bell and Rossman as estimating that the man tle may contain a volume of water equal to 80% of the volume of the world's oceans. Even if this Bell and Rossman estimate of mantle water seems high, one must still account for the hydrous and nominally hydrous minerals in Earth's crust. Therefore, having students assume that the solid Earth may contain water equal to 80% of the volume of the world's oceans may be a conservative estimate. For information on recycling of water into Earth's mantle, refer to: C. Meade and R. Jeanloz. 1991. Deep -focus earthqua kes and recycling of water into Earth's mantle. Science 252:68 –72. © 2015 Pearson Education, Inc. 11 LAB 1 ANSWER KEY ACTIVITY 1.1: Geologic Inquiry 1.1A. Observation, analysis, and description of the parts of Figure 1.1 12 © 2015 Pearson Education, Inc. 1.1B. Every part of Figure 1.1 shows objects that contain copp er (Cu). 1.1C. Analyze Figure 1.1 and answer the following questions. 1.1D. 1. The best location for a new mine (pit) is location C, because the rocks there have the same pink -red color in the false -colored satellite image as the rocks of the current a nd old copper mine pits. 1.1D . 2. To see if location C is actually a good source for more copper ore , one must go there to collect samples of the rock and determine if it contains copper - bearing minerals in profitable quantities to be mined. © 2015 Pearson Education, Inc. 13 ACTIVITY 1.2 : Spheres of Matter, Energy, and Change 1.2A. 14 © 2015 Pearson Education, Inc. 1.2B. answer sheet © 2015 Pearson Education, Inc. 15 1.2C. Completed Venn diagram 1.2D. Reflect and Discuss: Do you think that most change on Earth occurs within individual systems, at boundaries between two systems, or at the in tersections of more than two systems? Why? In general, one might expect that at the most change occurs at intersections of more than two systems, because there are more varied materials and energy forms (than in one system or the boundary between just two systems). 16 © 2015 Pearson Education, Inc. ACTIVITY 1.3 : Modeling Earth Materials and Processes 1.3A. 1. See the completed basketball model below. Students should realize that it is nearly impossible for them to draw separate lines for hydrosphere and atmosphere (because they are so na rrow compared to the diameter of the basketball). The crust will be about the thickness of a pencil/pen line. You could have students use another color of pencil for the crust (i.e., as done in red below). © 2015 Pearson Education, Inc. 17 1.3A. 2. The radius of the basketball model is 0.119m (119 mm), but the actual radius of Earth is 6,371,000 m, so the ratio scale of model to actual Earth is 0.119 to 6,371,000. Dividing 6,371,000 by 0.119 reduces the ratio scale to 1: 53,537,815. Thus, the basketball model is 1/53,537,815th of the actual size of Earth. Fractional scale : 1/53,537,815 Ratio scale : 1:53,537,815 1.3B. MODELING LANDSLIDE HAZARDS 1. If you lift one end of the ruler, then the coin slides towards the opposite end. 2. The coin did not slide off of the ruler at the very second you started to lift one end of the ruler, because there was friction between the coin and the ruler. 3. The coin start sliding when the force of gravity overcame the friction between coin and ruler. 4. REFLECT & DISCUSS: When s tudents describe how they would modify the ruler and coin model , their answers will vary widely. Most will use different solid materials, such as rocks on a piece of marble. Some will introduce water. Some will introduce wind. Some will want to measure va lues and graph results. ACTIVITY 1.4: Measuring and Determining Relationships 1.4A. The mathematical conversions (using the table on laboratory manual page xi) are: 1. 10.0 miles x 1.609 km/mi = 16.09 kilometers (or rounded to 16.1 km ) 2. 1.0 foot x 0 .3048 m/ft = 0.3048 meters (or rounded to 0.3 m ) 3. 16 kilometers x 1000 m/km = 16,000 meters 4. 25 meters x 100 cm/m = 2500 centimeters 5. 25.4 mL x 1.000 cm3/mL = 25.4 cm3 6. 1.3 liters x 1000 cm3/L = 1300 cm3 1.4B. 1. 6,555,000,000 = 6.555 x 109 2. 0.000001234 = 1.234 x 10-6 1.4C. Students should be able to use a metric ruler (cut from GeoTools sheet 1 or 2) to draw a line segment like this one that is exactly 1 cm long. _____ 1 cm 1.4D. Students should be able to use a metric ruler to draw a square that is exactly 1 cm long by 1 cm wide. [Note that this is a two -dimensional shape called a square centimeter, or cm2.] 1 cm 1 cm 18 © 2015 Pearson Education, Inc. 1.4E. Students will have some difficulty drawing a three -dimensional cubic centimeter on two -dimensional paper because the dimensions must be distorted to give the drawing its perspective view. However, their drawing of a cubic centimeter should be as close as possible to actual size. Some students will try to trace the cubic cen timeter in Figure 1.11B (which is correct, but must be traced exactly). 1.4F. Students should explain a procedure similar to this one and determine that water has a density of about 1 g/cm3: a. Fill a small graduated cylinder about halfway with water and r ecord this starting volume of water in the cylinder. The graduated cylinder will probably be graduated in mL (which equals cm3), so students should record the starting volume of water in cm3. b. Weigh the graduated cylinder of water from step a and record the starting mass of water in grams. c. Add a small amount of water to the graduated cylinder and: Read and record this ending volume of water. Weigh and record this ending mass of water. d. Use the following mathematical formula to determine the density of water: Ending mass of water (g) – starting mass of water (g) ————————————————————————— = about 1 g/cm3 Ending volume of water (cm3) – starting volume of water (cm3) 1.4G. Students will determine that their clay has a density greater than 1 g/cm3. Most brand s are between 2 g/cm3 and 4 g/cm3. There are two main methods/procedures that students use to determine this. Method 1 procedures : a. Construct a cubic centimeter of clay (1 cm3 of clay). b. Weigh the cm3 of clay in grams. This is the grams per cubic centimeter (density) of the clay. Method 2 procedures : a. Weigh a small lump of clay (that will fit in a graduated cylinder) and record its mass in grams. b. Fill the graduated cylinder about halfway with water and record the exact starting volume of water in cubic centi meters. c. Place the lump of clay into the water (do not splash) of the graduated cylinder and record this ending volume of water in cubic centimeters. d. Determine the volume of the clay by subtracting the starting volume of water in the graduated cylinder ( b) from the ending volume of water in the graduated cylinder ( c). e. Determine the density of the clay by dividing the mass of the clay sample ( a) by the volume of the clay sample ( d). © 2015 Pearson Education, Inc. 19 1.4H. 1. Clay sinks in water because it is more dense than water (it has a density greater than 1 g/cm3). 2. Some students will try to flatten the clay into a sheet that can float on the surface tension of the water. Other students will try to make a boat or a clay sphere. (If students are having great difficulty getting the en tire lump of clay to float, then you can ask them to consider how the Navy gets steel to float — i.e., it makes the steel into ship shapes.) 3. When students eventually make a ship shape (or sphere) and get their clay to float, then they should realize tha t the clay floated because it took on a new shape with a larger volume. This decreased the density of the clay and increased its buoyancy. 1.4I. Reflect and Discuss: The hydrosphere (liquid water) is less dense than the lithosphere, so it sits on top of the lithosphere. The atmosphere is the least dense of them all, so it occurs above them. In summary, the spheres are most dense at Earth's center and less dense with position away from Earth's center. Many students will draw this relationship and label the spheres. 1.4J. RATES: 1. a. 1.6 km x 1,000,000 mm/km = 1,600,000 mm 6 million years = 6,000,000 yr So: 1,600,000 mm ÷ 6,000,000 yr = 0.2666666 mm/yr = 2.666666 x 10-1 mm/yr b. 0.2666666 mm/yr times the age of the student in years = answer 2. 60°C ÷ 3.9 km = 15.38 °C/km 1.4K. Single Line Graph 20 © 2015 Pearson Education, Inc. 1. The amount of CO 2 in the atmosphere at Mauna Loa Observatory, Hawaii has increased every decade since 1962 . 2. The values for carbon dioxide increase as the years increase, and the line has a positive slope. 1.4L. Bar Graph 1.4M. Two -line Graph 1. The relationship revealed in this graph is that there is a close correlation between atmospheric carbon dioxide (ppmv) and global temperature. When carbon dioxide levels are, the temperature i s high. When carbon dioxide is low, then the temperature is low. Over the past 400,000 yr, both factors have risen and fallen together in cycles lasting about 100,000 yr. Carbon dioxide concentrations did not exceed 300 ppmv in any of those natural cycles or drop below 180 ppmv in any of those natural cycles. 1.4N. Reflect and Discuss Graph K and M show that since at least 1962, carbon dioxide levels have been higher than at any time in the past 400,000 years and reached a level of 393 ppmv in 2012. Graph L shows that the rate of carbon dioxide increase is also rising. One can expect the level and rate to increase in the future by extrapolating the graphs into the future. Also, based on Graph M, the levels of carbon dioxide in our atmosphere are greater tha n at any time in the past 400,000 years. Graph M also shows that global temperature and carbon dioxide concentrations rise and fall together, so one can infer that abnormally high global temperatures will accompany the abnormally high carbon dioxide levels of the future. © 2015 Pearson Education, Inc. 21 ACTIVITY 1. 5: Density, Gravity, and Isostasy 1.5A. Student answers will vary according to the type of wood. However, students should realize that they can determine the mass of the wood block by weighing it in grams (g). They should b e able to determine the volume of the wood block by using a ruler to measure its three linear dimensions in cm, and then multiplying the dimensions together to find the volume in cubic centimeters (cm3). The density of the wood block is its mass in grams d ivided by its volume in cubic centimeters. 1.5B. Bear in mind that the proportions of wood above and below the waterline will vary according to the type of wood. Pine floats higher than walnut. Exact measurements recorded by students will also vary accord ing to type of wood and size of the block. 1.5C. The exact form of equations will vary from student to student. The common form is: Hbelow = (Ρwood ÷ Ρ water) H block 1.5D. The exact form of equations will vary from student to student. Using the equation above (answer to Question 17), the common form would be: Habove = 1 – [ (Ρ wood ÷ Ρ water) H block ] 1.5E. The density of water ice (in ice bergs) is 0.917 g/ . The average density of (salty) ocean water is 1.025 g/ . 1. % below = (0.917 g/cm3 ÷ 1.025 g/cm3) 100% = 89.5% 2. % above = 100% – [(0.917 g/cm3 ÷ 1.025 g/cm3) 100%] = 10.5% 3. Students will generally find that their grid estimations of the percentages of the iceberg below and above sea level are consistent with their calculations above. 4. As the top of the iceberg melts, its submerged base will rise to establish a new isostatic equilibrium. 1.5F. Where mountains h ave been eroded, their ―roots‖ are still rising very slowly, so ancient shorelines become elevated above the levels where they originally formed. 22 © 2015 Pearson Education, Inc. ACTIVITY 1. 6: Isostasy and Earth’s Global Topography 1.6A. Student values for the density of pieces of ba salt that they personally analyze will vary from about 2.9 g/cm3 to 3.3 g/cm3. However, they should still determine that the average density of all 10 basalt samples is about 3.1 g/cm3. 1.6B. Student values for the density of pieces of granite that they p ersonally analyze will vary from about 2.7 g/cm3 to 3.2 g/cm3. However, they should still determine that the average density of all 10 granite samples is about 2.8 g/cm3. 1.6C. 1. Habove = 5 km – [ (3.1 g/cm3 ÷ 3.3 g/cm3) 5 km ] = 0.3 km 2. Habove = 30 km – [ (2.8 g/cm3 ÷ 3.3 g/cm3) 30 km ] = 5.0 km 3. 5.0 km – 0.3 km = 4.7 km 4. The calculated value of 4.7 km in part c is close to the actual difference between the average height of the continents and the average depth of the oceans on the hypsographic curve in Figure 1.11. 1.6D. Reflect and Discuss: Earth has a bimodal global topography because its granitic continental blocks of lithospheric rock have an average density that is less than the average density of basaltic sea floor rocks . Thus, on average, the continental blocks sit about 4.53 kilometers higher in the mantle than the basaltic blocks. Oceans cover the basaltic blocks, but the tops of continental blocks remain above sea level. 1.6E. Reflect and Discuss: As a mountain forms , it establishes a level of isostatic equilibrium in the denser mantle —a sort of ―mantle line‖ (like the waterline on an iceberg). In other words, most of the mountain is a submerged ―root,‖ just as most of an iceberg is its ―root‖ below sea level. As a mo untain is eroded, its root rises to establish a new level of isostatic equilibrium. 1.6F. Reflect and Discuss: Students can take and defend any inference, but the best and most correct inference is one that is supported by data and good logic. The most correct proposal (according to their work in this laboratory) is a compromise hypothesis stating that: Blocks of Earth’s crust (actually lithosphere) have different densities (Pratt) and different thicknesses (Airy), so they sink to different compensation l evels. © 2015 Pearson Education, Inc. 23 LABORATORY TWO Plate Tectonics and the Origin of Magma BIG IDEAS: Tectonics is the study of g lobal processes that create and deform lithosphere. Plate tectonics is the theory that Earth’s lithosphere is bro ken into dozens of plates (thin curved pieces). The pl ates are created and destroyed, move about, and interact in ways that cause earthquakes and create major features of the continents and ocean basins (like volcanoes , mountain belts, ocean ridges, and trenches). THINK ABOUT IT (Key Questio ns): Is the lithosphere beneath your feet really moving? (Activity 2.1) What causes plate tectonics? (Activities 2.2, 2.3) How are plate boundaries identified? (Activities 2.4, 2.5, 2.6, 2.7) How and at what rates does plate tectonics affect earth’s surfac e? (Activities 2.4, 2.5, 2.6, 2.7) What are hot spots, and how do they help us explain plate tectonics? (Activity 2.8) How and where does magma form? (Activity 2.9) STUDENT MATERIALS (Remind students to bring items you check below.) _____ laboratory m anual with worksheets linked to the assigned activities _____ computer with Internet access (Activities 2.1 and 2.8 only) _____ laboratory notebook _____ pencil with eraser _____ metric ruler (cut from GeoTools sheet 1 or 2) _____ protractor (cut from GeoT ools sheet 4) _____ calculator _____ plastic ruler or popsicle stick (Activity 1.2) _____ colored pencils (red and blue) _____ visual estimation of percent chart (cut from GeoTools sheet 1 or 2) INSTRUCTOR MATERIALS (Check off items you will need to prov ide.) ACTIVITY 2.1: Plate Motion Inquiry Using GPS Time -Series _____ extra metric rulers (for students who forgot them ) 24 © 2015 Pearson Education, Inc. ACTIVITY 2.2: Is Plate Tectonics Caused by a Change in Earth’s Size? _____ extra metric rulers (for students who forgot them ) ACTIVITY 2.3: Lava Lamp Model of Earth _____ extra blue pencils (for students who forgot them) _____ extra red pencils (for students who forgot them) _____ extra plastic rulers or popsicle sticks, so each student has one _____ Silly Putty TM _____ la va lamp (turned on at least one hour ahead of time) and/or la va lamp video clip ACTIVITY 2.4: Paleomagnetic Stripes and Seafloor Spreading _____ extra metric rulers (for students who forgot them ) ACTIVITY 2.5: Atlantic Seafloor Spreading _____ e xtra metric rulers (for students who forgot them) _____ extra blue pencils or pens (for students who forgot them) _____ extra red pencils or pens (for students who forgot them) ACTIVITY 2.6 : Using Earthquakes to Identify Plate Boundaries _____ extra metric rulers (for students who forgot them) _____ extra red pencils or pens (for students who forgot them) ACTIVITY 2.7: San Andreas Transform -Boundary Plate Motions _____ extra metric rulers (for students who forgot them) ACTIVITY 2.8: Hot Spots and Plate Motions _____ extra metric rulers (for students who forgot them) ACTIVITY 2.9 : The Origin of Magma _____ extra metric rulers (for students who forgot them) _____ hot plate (one per group of students) _____ sugar cubes (two per group of st udents) _____ dropper with water or dropper bottle (one per group of students) _____ aluminum foil (one sheet per group of students) or foil baking cups (two per group of students) _____ crucible tongs (one per group of students) _____ permanent f elt-tip marker (one per grou p of student) INSTRUCTOR NOTES AND REFERENCES 1. Metric and International System of Units (SI): refer to laboratory manual page x i. 2. Mathematical conversions: refer to laboratory manual page xi i. © 2015 Pearson Education, Inc. 25 3. To model Kinetic Theory, place small plastic or glass marbles in a clear plastic box or tray on an overhead projector. Hold the model still and elevated at one end, so the marbles form a close -packed array resembling a crystalline solid structure. Vibrate the model slightly to model a r ise in kinetic energy and to start moving the marbles apart, as if melting is initiating. Vibrate the model more to model a greater rise in kinetic energy and to cause all of the marbles to move about independently, as if total melting or vaporization has occurred. (To model crystallization by decreasing kinetic energy, repeat these tasks in reverse.) Note: be sure to remind students that plumes of Earth’s mantle are rock, not liquid magma or lava. 4. One lava lamp, or two, or three? Most lava lamps must be l ighted for at least one hour before they exhibit active and obvious convection. It helps to have two or more lamps that have been turned on at different times, so the ―lava‖ (wax) has varying amounts of kinetic energy. This helps students understand kineti c theory and how unequal amounts of heating affect the development and rate of convection. A lava lamp video clip is provided on the IRC -DVD. Note: be sure to remind students that Earth’s mantle is rock, not liquid magma or lava. 5. Decompression melting. To help students visualize decompression melting, have them mix corn starch and water to make a corn starch suspension. Then have them try to roll some of the suspension into a ball and watch the suspension flow through their fingers. So long as the suspensi on is under pressure (i.e., while it is being rolled into a ball), it remains in a solid -like state. When the suspension is not under pressure (i.e., when a ball of suspension is placed on the palm of a hand), it flows in a liquid state. This is NOT decomp ression melting, but it helps students understand that pressure can prevent flowing even in materials that are normally fluid. 6. To model mantle plumes and hot spots, make a model of Earth’s compositional layering first by placing clear corn syrup in a cle ar plastic cup (to represent Earth’s mantle) and then by adding a few mm of water on top of it (to represent Earth’s crust). To prepare material for a mantle plume, heat a small amount of corn syrup (with a few drops of red food coloring) on a hot plate. Fill a dropper with the hot red corn syrup, and then squeeze some of it out onto the bottom of the plastic cup containing the cool syrup and water. Watch as the hot red corn syrup rises through the cooler corn syrup to form a long narrow plume and a pool of red syrup just beneath the water (crust). This is especially useful for having students entertain ideas about the origin of hot spots. 7. Flux melting. In the smelting industry, the term ―flux‖ refers to materials such as ―fluxstone‖ that are added to raw o re in order to lower the fusion (melting) temperature and produce slag. Experimental petrology has demonstrated that water lowers the fusion temperature of some minerals commonly found in granite, basalt, and peridotite , thereby initiating partial melting at lower, ―wet solidus‖ temperatures.