Transcript ppt wegener
8th Grade Content Statement The composition and properties of Earth’s interior are identified by the behavior of seismic waves. The refraction and reflection of seismic waves as they move through one type of material to another is used to differentiate the layers of Earth’s interior. Earth has an inner and outer core, an upper and lower mantle, and a crust. The formation of the planet generated heat from gravitational energy and the decay of radioactive elements, which are still present today. Heat released from Earth’s core drives convection currents throughout the mantle and the crust. 8th Grade Content Statement Earth’s crust consists of major and minor tectonic plates that move relative to each other. Historical data and observations such as fossil distribution, paleomagnetism, continental drift and sea-floor spreading contributed to the theory of plate tectonics. The rigid tectonic plates move with the molten rock and magma beneath them in the upper mantle. Convection currents in the crust and upper mantle cause the movement of the plates. The energy that forms convection currents comes from deep within the Earth. 8th Grade Content Statement A combination of constructive and destructive geologic processes formed Earth’s surface. From the elaboration - Distinguishing between major geologic processes (e.g., tectonic activity, erosion, deposition) and the resulting feature on the surface of Earth is the focus of this content statement. How do the pieces fit together? • Cut the pieces out. • Take 5 minutes to work with them. • Discuss your arrangement with a fellow scientist. • As a pair write your claim and provide evidence on large chart paper. – CLAIM - How would you put them together? – EVIDENCE – Explain your reason(s) for arranging the pieces the way you did. Scientist Meeting Share out claim and evidence Can the whole group come to a common agreement? What is this? “Supercontinent” Pangea What is this? By 1570, European explorers had mapped most of the Earth. People looked at these maps and began to notice, what? What do you think caught their eye? What do you notice? 1620 Sir Francis Bacon noticed… That the continents fit together! Do you agree? Where do you see it? Alfred Wegener also noticed… Wegener was not the first to notice the fit of Africa and South America, but he was the first to collected evidence to support his theory! Let’s look at what he found… http://www.ucmp.berkeley.edu/geolo gy/techist.html Take a second look… Alfred had 3 pieces of evidence to support his claim…What are they? Color the puzzle pieces according to the key Wegener’s Evidence Natural Fit - Students should understand that using the shape of the continents to fit them back together is using one type of evidence. Fossils - Using the presence of the same type and age fossils is another. Rock Type - The presence of the same rock types is another form of evidence. Anything else? Can you think of other types of evidence to search for that might be useful in solving their puzzle. There are other directions, but... It is far more important to have students grasp the concept of how scientists look for clues, or evidence, and put the pieces together to solve a problem. The conversation the students engage in is the richest part of the lesson. • Briefly present background on Wegener. Stress that although others had recognized the fit of Africa and South America, it was Wegener who gathered other scientific data to support his theory. • Divide students into groups of two or three. These small groups allow students to discuss the significance of different lines of evidence as they piece together the continental puzzle. • Each group is given a cut-out sheet containing fossil evidence (Student Puzzle Pieces), the Key to Wegener's Evidence sheet, the Student Map of the World Today reference sheet, crayons or markers, and a pair of scissors. • Groups label the continents or land mass on each piece. The students then color each fossil type and the Key to Wegener's Evidence sheet. Then cut out the land masses from the evidence sheets. • Have the students arrange the puzzle pieces using the Key to Wegener's Evidence to support their arrangement. • The final puzzle configuration should be attached to paper with glue or tape. • When finished, each group will present and defend their reconstruction. • You may compare the students' reconstructions with Wegener's Key to Continental Positions about 250 million years ago (Teacher Copy) Standing Cube 4 Sides Alfred Wegener’s picture and his contribution to science Pangea with explanation/definition Wegener’s Claim, Evidence, Reasoning 30 years later… You Tube • http://www.cleanvideosearch.com/media/a ction/yt/watch?v=T1-cES1Ekto Plate Tectonics • • • • • • Foldable - Layers of the earth Paper Model of sea floor spreading Transparency Demo Intranet Resources Active Art Models/examples of convection currents – http://www.youtube.com/watch?v=ft-dP2D7QM4 – http://www.youtube.com/watch?NR=1&v=KCSJNBM OjJs&feature=endscreen Heat Up the Floating Plates • Offers a working model of convection currents… Say what? The extreme heat in the center of the earth causes convection currents in the asthenosphere which is made of hot molten material on which the lithospheric plates move. Break it down Have students rewrite and then refine the statement as new vocabulary is defined Example: The center of the earth is very hot! Heat rises from the center of the earth and causes the mantel (the hot melted rock layer of the earth) to move. The crust (the surface of the earth) is broken into plates and they move. Theory Their statement: The extreme heat in the center of the earth causes convection currents in the Our statement Heat rises from the center of the earth and causes the mantel (the hot melted rock layer of the earth) to move. Fact Their statement: asthenosphere which is made of hot molten material on which the lithospheric plates move. Our statement: The crust (the surface of the earth) is broken into plates and they move. The extreme heat in the center of the earth causes convection currents in the asthenosphere which is made of hot molten material on which the lithospheric plates move. Stream Tables Observe Erosion Deposition Investigate Standard water source Flood water source Slope What evidence could you use to construct one “Supercontinent”? CER - Claim, Evidence, Reasoning Claim The continents were once one large land mass. Using Wegener’s Puzzling Evidence construct a “supercontinent” What evidence can you provide to support Wegener’s theory that the continent are moving and were once a supercontinent?