Thursday 11/30/17 Notebook Entry: Look at the image below. What do you think the image is showing you? What do you think the different colors are supposed to tell you?

What other evidence could support Wegener’s idea The ocean floor gives us many clues…how did we find these clues? Marie Tharp’s Maps Mapping with Sonar

Map of the Earth’s Mid-Ocean Ridges

Scientists Build on Previous Ideas Harry Hess Geologist and Navy submarine commander during World War II In 1960 he proposed sea-floor spreading based on observations of the East Pacific Rise

East Pacific Rise

SEA-FLOOR SPREADING Process by which molten material adds new oceanic crust to the ocean floor. Occurs along a mid-ocean ridge. Where are the mid-ocean ridges on your map? Older oceanic crust moves away from ridge.

Sea-Floor Spreading at Mid-Ocean Ridge

Subduction When ocean crust meets less dense rock in the crust it sinks below the less dense rock because of gravity Forms a deep-ocean trench = a place where ocean crust bends downwards. Where would the deep-ocean trenches be on the map?

Subduction at Deep Ocean Trench

What is a model? A model is a representation of something else. Can show an object or process Models help us to understand how the real things work The model may look like, function like, describe, or explain the real thing.

Modeling Sea-Floor Spreading How does sea-floor spreading add material to the ocean floor and what happens to this material over time? Goal = Model sea-floor spreading and subduction along with the key landforms these two processes create.

Putting your model together…

Procedure START MYA 180 MYA 160 MYA 140 MYA 110 MYA 90 MYA 60 MYA Fold the paper in half lengthwise and write the word “Start” at the top of each half of the paper. Use the ruler and pencils to draw and color stripes across the paper. The stripes should look like the picture to the right. In each stripe write the age of the crust as also shown in the picture (MYA = million years ago) Using the scissors, carefully cut the paper in half along the fold line to form two strips.

Procedure Following Mrs. Burke fold the second sheet of paper crosswise into eighths as shown. Then unfold it, leaving creases in the paper. Now fold the second sheet of paper in half crosswise. Starting at the center fold, draw lines 5.5 cm long on the middle crease

Procedure Repeat the 5.5 cm line on the two creases closest to the ends of the paper. Raise your hand so Mrs. Burke can check your lines. Carefully cut along the lines you drew. Unfold the paper. There should be three slits, each 11 cm long, in the center of the paper as shown below.

Homework Read and do pages 84-85 I will be checking your textbook tomorrow for completion of the reading pgs. 80-85

Friday 12/1/17 Notebook Entry: Look at the picture below. Describe how convection in the mantle could cause sea-floor spreading?

Procedure START MYA 180 MYA 160 MYA 140 MYA 110 MYA 90 MYA 60 MYA Fold the paper in half lengthwise and write the word “Start” at the top of each half of the paper. Use the ruler and pencils to draw and color stripes across the paper. The stripes should look like the picture to the right. In each stripe write the age of the crust as also shown in the picture (MYA = million years ago) Using the scissors, carefully cut the paper in half along the fold line to form two strips.

Putting your model together…

Vocabulary Card Assignment Due Thursday 12/7/17 Make cards for the following terms: Continental Drift Sea-floor spreading Subduction Remember to copy definition from your textbook. Use your book to help you with completing your card.

Monday 12/4/17 Fill out your assignment notebook for the week. Today will be a work day to catch up on work that is incomplete or missing.

Tuesday 12/5/17 Notebook Entry: Examine the graphic and it’s key. At which feature is new sea-floor being made? What do you predict would happen to the size of the sea-floor over time as new sea-floor is continually being made? (At the ridge shown in the graphic about 12.6 inches (32.2 cm) per year is added).

Sea-Floor Spreading & Subduction

T = Continental Drift Evidence Sea-floor Evidence The age of the rock that makes up the sea floor is not the same. At mid-ocean ridges molten material is being forced out & creating new ocean crust. The youngest rock is located here. This process is called sea-floor spreading and is the force pushing the continents.

Turn in the question sheet when done Analyze and Conclude Questions You can work with your partner and use the textbook to help you analyze the model. Turn in the question sheet when done If you don’t finish in class you need to finish for homework that is due tomorrow. One team member keeps the model.