OCEAN FLOOR TOPOGRAPHY BACKGROUND THE LITHOSPHERE IS THE CRUST AND TOP OF THE MANTLE, SIMILAR TO TAKING THE CRUST OFF THE TOP OF A DUTCH APPLE PIE. THE LITHOSPHERE IS MADE UP OF PLATES. A PLATE IS A MOVING PIECE OF LITHOSPHERE. THERE ARE 7 MAJOR PLATES AND MANY MINOR PLATES WHICH ARE MOVING. THE PLATES ARE MOVING FROM 2 – 10 cm/yr, ABOUT THE RATE AT WHICH FINGERNAILS GROW. THE WATER ON OR NEAR THE SURFACE COVERS 71.13% OF THE SURFACE OF THE EARTH. THIS IS THE OCEANS, RIVERS, LAKES, AND MOISTURE IN THE AIR. THE OCEAN PROVIDES ~80% OF THE O2 AND STORES ~97% OF EARTH’S H2O. THE OCEAN CONTAINS ~90% OF THE BIOMASS, HOLDS ~90% OF ITS LIFE IN THE TOP 100 m, AND PROVIDES HABITAT FOR ~50% (~1 MILLION) OF ALL SPECIES. THE OCEAN HAS AN AVERAGE DEPTH OF 4,000 m, AND PROVIDES ~17 % OF JOBS IN THE US. ~60% OF OCEAN SPECIES REMAIN UNDISCOVERED AND MORE THAN 95% OF THE OCEAN REMAINS UNEXPLORED. OCEAN FLOOR SPREADING EXPLAINS THAT THE FORMATION OF NEW OCEAN FLOOR MOVES THE CONTINENTS. THE OCEAN FLOOR IS MOVED AS A RESULT OF THE FORMATION OF NEW OCEAN FLOOR AND AT THE SAME TIME NEW FLOOR IS CREATED, THE OLD FLOOR IS DESTROYED. THE CONTINENTS ARE MOVED AS A RESULT OF OCEAN FLOOR MOVEMENT. THE FEATURES OF THE OCEAN FLOOR ARE AS DIVERSE AS THE LAND. RIFT VALLEYS OCCUR WHERE THE PLATES MOVE APART. MAGMA EXTRUDES BETWEEN THE PLATES AND FORM UNDER WATER MOUNTAIN CHAINS. TRENCHES OCCUR WHERE PLATES COME TOGETHER. WHEN PLATES COLLIDE, 1 PLATE SLIDES UNDER THE OTHER AND FORMS TRENCHES. TRENCHES ARE WHERE OLD OCEAN FLOOR IS DESTROYED. THE CONTINENTAL SHELF IS PART OF THE CONTINENTAL CRUST THAT EXTENDS INTO THE OCEAN. THE CONTINENTAL SHELF TRANSFORMS INTO THE CONTINENTAL SLOPE AND MEETS THE OCEAN FLOOR. THE OCEAN FLOOR SLOPES STEEPLY DOWN TO THE OCEAN BASIN OR ABYSSAL PLAIN. THE ABYSSAL PLAIN IS THE FLAT OPEN PLAIN OF THE OCEAN FLOOR. SEAMOUNTS ARE UNDERWATER PEAKS WITH DIFFERENT SHAPED TOPS. SONAR, SOUND NAVIGATION AND RANGING, IS A TOOL USED TO MAP THE OCEAN FLOOR. SOUND WAVES TRAVEL FURTHER IN WATER THAN DO LIGHT AND RADAR WAVES. SONAR IS USED TO DEVELOP NAUTICAL CHARTS WHICH SHOW THE CONFIGURATION OF THE SHORELINE, SEA FLOOR, AND WATER DEPTHS. SONAR ALSO PROVIDES LOCATIONS OF DANGERS TO NAVIGATION AS WELL AS LOCATIONS AND CHARACTERISTICS OF AIDS TO NAVIGATIONS SUCH AS ANCHORAGES. THERE ARE 2 TYPES OF SONAR, ACTIVE AND PASSIVE. ACTIVE SONAR EMITS A SIGNAL AND RECEIVES THE “ECHO” TO DETERMINE THE RANGE AND ORIENTATION OF OBJECTS. PASSIVE SONAR DOES NOT EMIT A SIGNAL, IT DETECTS SOUND WAVES AND CAN NOT DETERMINE THE RANGE AND ORIENTATION OF OBJECTS.

ACTIVE SONAR

PASSIVE SONAR

OCEAN DEPTHS CAN BE MEASURED AND MAPPED USING THE SONAR DATA AND THE FORMULA:

D = ½ (T x V), WHERE D = DEPTH, T = TIME, AND V = VELOCITY WHICH IN WATER AT 20o C IS 1.5 Km/s. 1. CALCULATE THE DEPTH OF THE OCEAN FLOOR 2. ROUND RESULTS TO THE ONE AND TENTHS PLACE

SONAR DATA COLLECTED FROM SHORE TO OPEN OCEAN DIST (Km) 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 TIME (s) 0.13 0.27 0.53 2.65 2.65 2.92 4.25 4.25 2.65 1.86 1.33 3.98 4.51 6.10 6.90 12.25 14.60 6.64 7.96 7.43 DEPTH (Km)

II. MATERIALS PENCIL COLORED PENCILS STRAIGHT EDGE GRAPH PAPER DATA TABLE III. PROCEDURE 1. ORIENT PAPER SO THAT LONG EDGE IS AT THE BOTTOM 2. LABEL THE TOP OF THE GRAPH WITH DESCRIPTIVE TITLE “TOPOGRAPHY OF THE OCEAN FLOOR” 3. COUNT IN FROM THE LEFT SHORT EDGE 5 LINES AND MAKE A SMALL MARK 4. ON THE 5TH LINE, DRAW A LINE FROM TOP TO BOTTOM OF PAPER, THIS IS THE Y AXIS 5. COUNT IN 2 LINES FROM THE LEFT SHORT EDGE SIDE AND LABEL THE Y AXIS “DEPTH (Km)” 6. COUNT UP FROM THE BOTTOM LONG EDGE 5 LINES AND MAKE A SMALL MARK 7. ON THE 5TH LINE, DRAW A LINE FROM LEFT TO RIGHT ACROSS PAPER, THIS IS THE X AXIS 8. COUNT UP 2 LINES FROM BOTTOM LONG EDGE AND LABEL THE X AXIS “DISTANCE FROM SHORE (Km)” 9. ON THE X AXIS, LABEL THE ORIGIN 0 AND LABEL EVERY OTHER LINE NUMERICALLY BY 10’S UP TO 200 10. ON THE Y AXIS, BEGIN AT ORIGIN AND LABEL EVERY LINE NUMERICALLY BY 0.5 ‘S UP TO 12.0 11. USE BLUE DOTS TO PLOT THE DEPTH 12. CONNECT EACH DOT WITH A BLUE LINE 13. CREATE A KEY ON THE GRAPH IV. RESULTS THIS IS THE COMPLETED GRAPH

CONTINENT

MID OCEAN RIDGE CONTINENTAL SHELF

TRENCH

ABYSSAL PLAIN

CONTINENTAL SLOPE

1. IDENTIFY THE FEATURES OF THE OCEAN FLOOR 2. COLOR EACH FEATURE THE CORRESPONDING COLOR 1. MID OCEAN RIDGE, RED 2. CONTINENTAL SHELF, BLUE 3. TRENCH, BLACK 4. CONTINENT, GREEN 5. ABYSSAL PLAIN, ORANGE 6. CONTINENTAL SLOPE, PURPLE

1. USE BLUE DOTS TO PLOT THE OCEAN FLOOR USING DATA FROM “SONAR DATA COLLECTED FROM SHORE TO OPEN OCEAN” TABLE 2. CONNECT EACH DOT WITH A BLUE LINE

      0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210

DISTANCE FROM SHORE (Km) V. CONCLUSION 1. DESCRIBE HOW ACTIVE SONAR IS USED TO MAP THE OCEAN FLOOR. 2. WHAT IS THE FORMULA FOR CALCULATING OCEAN FLOOR DEPTH? 3. DESCRIBE OCEAN CURRENTS. 4. WHAT PERCENT OF SURFACE IS COVERED BY WATER? 5. HOW MANY MAJOR CURRENTS ARE IN THE OCEANS? 6. WHAT CREATES CURRENTS? 7. WHAT DOES THE OCEAN EFFECT? 8. AFTER THE SUN, WHAT HAS THE MOST EFFECT ON CLIMATE? 9. DESCRIBE CLIMATE. 10. DESCRIBE WEATHER.

11. LIST AND DESCRIBE THE 3 TYPES ENERGY TRANSFER. 12. OCEAN CURRENTS ARE CONVEYER BELTS, WHAT DO THEY TRANSPORT? 13. DESCRIBE SURFACE CURRENTS. 14. DESCRIBE DEEP WATER CURRENTS 15. DESCRIBE TOPOGRAPHY. 16. WHAT IMPACTS CURRENTS BY REDIRECTING CURRENTS. 17. WHAT DO SURFACE CURRENTS TRANSPORT AND DISTRIBUTE GASES.

 

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