Monday March 12, 2011 AND Tuesday March 13, 2012

DeepEarthAcademy lesson- “Sediment Deposition Supports Seafloor Spreading”(can be found under “Seafloor Spreading” from Mrs. Magrini’s homepage)

DO NOW:

  • Log onto computer, open Google Earth, download the Google Overlay file “Sediment Deposition Supports Seafloor Spreading”
  • Gather materials needed: Answer page, calculator,Ocean Exploration binder
  • Read the Background for “Sediment Deposition Supports Seafloor Spreading” in the Ocean Exploration binder

LESSON: Sonar Travel time & Sediment Thickness

GATHER DATA/ CALCULATIONS:follow directions under the data table

  • Using Google Earth, record the sonar travel time and sediment thickness for each site.
  • Calculate distance to the ocean floor using D= (V x T)/2 (you may use calculators!)

Mini Lesson: Graphing in the 4th quadrant

GRAPH: Depth to ocean floor & depth to basalt (will be a double line graph)

BELOW SEALEVEL. (directions can be found on the Answer Page below the data collected)

ANALYSIS: Complete analysis questions after creating the graph.

WRAP UP: Create an ISN entry titled “Sediment Deposition Supports Seafloor Spreading” (both right and left side)

On the left side…..Summarize how the data collected in the 1996 JOIDES Resolution expedition supported seafloor spreading.

  • Summarize where the data was collected- what ocean, name of plate boundary, what lithospheric plates are on either side, what type of boundary it is.
  • Describe what data was collected (sediment core samples- which measuredsediment thickness & sonar which measured distance to the ocean floor)
  • Describe how the data collected support the theory of seafloor spreading.

On the right side….. tape or glue in the data table and graph you are about to make on excel. (directions below)

EXCEL SPREADSHEET

  1. Open your “Seafloor Spreading” file on excel. (Or start a new one if yours was not saved.)
  1. Click on “sheet 2” tab. Right click to rename “JOIDES 1996.”
  1. Using the data collected on your answer sheet, create a data table including distance east of the ridge (km), depth to ocean floor (m), and depth to basalt (m)--- in that order. NOTE: since depth is below sea level, add a negative (-) sign in front of all depths.
  1. Highlight the data table
  • Chart wizard > line graph > choose subtype with “line marks displayed at each data value” (should be 4th choice) > NEXT > data range > NEXT > chart title “Juan de Fuca Seafloor Sediments”, x-axis: “distance from the ridge (km), y-axis: “depth (m)” > FINISH
  1. On the graph, click on the “distance east of the ridge” data and delete.
  1. Right click on the y-axis data > format axis > scale > change “maximum” to -2000 and change “major unit” to 500.

*To make your graph “colored” like the graphs you drew...follow these directions courtesy of JS!!

  • Insert > Pictures > AutoShapes > add small toolbar, click farthest to the left, or “Line”.
  • Then Freeform, should be 6th option.
  • Then you will click on all the points you want to add and to finish click “last point”