  What lies at the bottom of the ocean?

Exploring the Ocean Standards: S6E3.c – Describe the composition, location, and subsurface topography of the world’s oceans. S6CS3 – use computation to analyze scientific data.

Locate the Oceans On your map handout, label the 5 major oceans.

What do you know about the oceans? 1. Which ocean is the deepest? a. Atlantic b. Pacificc. Indian 2. Which ocean has the deepest point on the ocean floor? a. Atlantic b. Pacific c. Indian The Challenger Deep is the deepest point at 35,802 feet deep. It is located off the coast of Guam in the Marianas Trench. 3. Where is the world’s longest mountain range? a. Atlantic b. Pacific c. Indian 4. What is the smallest ocean? a. Atlantic b. Southern c. Arctic

Group discussion Why are the oceans so difficult to study? What kinds of technology would help scientists learn more about the deep- ocean floor?

Mapping the Ocean Floor Seeing by Sonar Sound Navigation and Ranging Technology is based on the echo- ranging behavior of bats. Purpose: Use to determine the ocean’s depth by sending sound pulses from a ship down into the ocean. Sound bounces off of the ocean floor and travels back to the ship. Time it takes for the signal to bounce back, determines the distances.

1970 Scientists starting using satellites. Seasat  images are used to study ocean currents. Geosat  Images used to measure slight changes in the height of the ocean’s surface.

Exploring the Ocean with Underwater Vessels Piloted Vessels: Alvin and Deep Flight  Two research vessels that can reach some of the deepest parts of the ocean. Robotic Vessels: JASON II and Medea  Jason explores the ocean floor, Medea is attached with a tether.

  Science Humor: What lies at the bottom of the ocean and trembles? A: a nervous wreck

Revealing the Ocean Floor   Using your textbook, pages 384 and 385, complete the ocean floor worksheet.   Label the pictures.

1. Continental shelf c. gently sloping area bordering a continent 2. Continental slope e. a steady incline starting at the end of a continental shelf 3. Seamount b. mountain whose peak does not break through the surface of the ocean. 4. Abyssal plain f. broad flat area covered with thick layers of mud and silt 5. Volcanic island d. a volcano on the ocean floor that creates a mountain big enough to break the ocean surface. 6. Mid-ocean ridge a. consists of many peaks along both side of a central valley. 7. Trench g. a long, narrow, and deep depression with steep sides on the ocean floor.

Continental Shelf Continental shelf Continental slope Seamount Volcanic island Continental rise Abyssal plain mid-ocean ridgeRift valley trench

Review 1. With sonar, what happens to sound pulses from a ship after they hit the ocean floor? A: they bounce back to the ship 2. What can scientist conclude the longer it takes sound to return to a ship? A: the deeper the ocean floor is in that spot 3. What are 4 ways that scientist study the ocean floor? A: sonar, piloted vessels, robotic vessels and satellites. 4. What is a guyot? A: flat-top seamount 5. Where is the mid-ocean ridge located? A: Atlantic ocean