Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Name ___________________________________ Date _________________ Lab Period _____ Lab Day ______ Crustal Speed Complete the chart Islands Distance in km Use map scale Distance in cm. km X 100,000 Age Difference in years subtract Hawaii and Maui Maui and Molokai Molokai and Oahu Oahu and Kauai Average XXXXXX XXXXXXX XXXXXXXX Speed In cm/yr Questions: Answer questions # 1 – 3 in complete sentences. 1. 2. 3. 4. A B C D 5. A B C D 6. A B C D 7. A B C D 8. A B C D Lab # 15 Crustal Speed Introduction: Most scientists believe that the earth’s crust is broken into pieces, much like the cracked shell of a hard-boiled egg. These pieces are called crustal plates and are thought to be moving across the mantle, the layer of earth directly below the crust. The diagram below illustrates how some scientists believe lines of volcanic islands are produced as superheated molten material rises upward from deep within the mantle. The molten material breaks through weak places in the crustal plates as the plates move over the top of the stationary hot spot (or plume) in the mantle. In the diagram, the first volcano is the oldest; the second and third are progressively younger. The fourth volcano in the diagram is directly over the hotspot, is the youngest, and is still active. Using the concept of volcanic island being formed over a stationary hot spot, it is possible to calculate the crustal speed. PROCEDURE: The following diagram shows the eight main islands of the Hawaiian chain. Approximate age is given for the larger islands. Using the scale shown on the diagram, determine the distance between the five major islands and enter the answers on the answer sheet in the data table. Measure the distance between the dots placed at the center of the major islands. Convert the distances from kilometers (map scale) to centimeters by multiplying the value in kilometers by 100,000 (1000 m/km and 100 cm/m). Enter the new value for distance in the data table. Calculate the approximate age differences between the islands and enter the data in the data table. You must subtract. Using the following formula, calculate the approximate speed at which the crustal plate was moving between the times that each of the islands formed. Speed of crustal movement (cm/yr) = Distance between the islands (in cm) _______________________________________ Difference in ages of the two islands (years) Calculate the average speed of the Pacific Plate. QUESTIONS: 1. In which direction was the crustal plate (Pacific) moving when the Hawaiian Islands were formed? Explain your answer. 2. A new Hawaiian Island is currently forming. Predict the location of the newest Hawaiian Island. 3. According to your data, did the crustal plate always move at as constant speed? Explain your answer. Use the map of the Hawaiian Islands to answer questions #4 through #6. 4. Why is Niihau Island much smaller than “The Big Island” of Hawaii. A. The are more people on Hawaii than Niihau B. The hot spot was much stronger when Niihau formed than when Hawaii formed C. The hot spot was much stronger when Hawaii formed than when Niihau formed D. Niihau is older and has been worn away by waves 5. Predict the age of Niihau. A. 3,000,000 years B. 3,500,000 years C. 4,000,000 years D. 4,500,000 years\ 6. If waves wear away (erode) the islands, where might you expect to find extinct volcanoes that are under water? A. North of Hawaii B. East of Maui C. Northeast of Oahu D. Northwest of Niihau 7. According to the map on page 5 of the Earth Science Reference Tables, which direction is the South American Plate moving? A. Northeast B. Northwest C. Southeast D. Southwest 8. According to the map on page 5 of the Earth Science Reference Tables, which direction is the African Plate moving? A. Northeast B. Northwest C. Southeast D. Southwest