What lies at the bottom of the ocean?

Exploring the OceanExploring the Ocean

Standards: Standards:

S6E3.c – Describe the S6E3.c – Describe the composition, composition, locationlocation, and , and subsurface topographysubsurface topography of the of the world’s oceans.world’s oceans.

S6CS3 – use computation to S6CS3 – use computation to analyze scientific data.analyze scientific data.

Locate the OceansOn your map handout, label the 5 major oceans.

What do you know about the oceans?

1. Which ocean is the deepest?a. Atlantic b. Pacific c. Indian

2. Which ocean has the deepest point on the ocean floor?

a. Atlantic b. Pacific c. IndianThe Challenger Deep is the deepest point at 35,802 feetdeep. 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 FloorMapping the Ocean FloorSeeing by SonarSeeing by Sonar

Sound Navigation and RangingSound Navigation and Ranging

Technology is based on the echo-Technology is based on the echo-ranging behavior of bats.ranging behavior of bats.

Purpose: Use to determine the Purpose: Use to determine the ocean’s depth by sending sound ocean’s depth by sending sound pulses from a ship down into the pulses from a ship down into the ocean.ocean.

Sound bounces off of the ocean floor Sound bounces off of the ocean floor and travels back to the ship.and travels back to the ship.

Time it takes for the signal to bounce Time it takes for the signal to bounce back, determines the distances. back, determines the distances.

1970 Scientists starting using satellites.1970 Scientists starting using satellites.

Seasat Seasat images are used to study images are used to study

ocean currents.ocean currents.

GeosatGeosat Images used to measure Images used to measure

slight changes in the slight changes in the height of the ocean’s height of the ocean’s surface.surface.

Exploring the Ocean with Underwater Exploring the Ocean with Underwater VesselsVessels

Piloted Vessels:Piloted Vessels:Alvin and Deep FlightAlvin and Deep Flight

Two research vessels that Two research vessels that can reach some of the can reach some of the deepest parts of the ocean. deepest parts of the ocean.

Robotic Vessels:Robotic Vessels:JASON II and MedeaJASON II and Medea

Jason explores the ocean Jason explores the ocean floor, Medea is attached floor, Medea is attached with a tether.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 shelf1. Continental shelf

c. gently sloping area bordering a continentc. gently sloping area bordering a continent

2. Continental slope2. Continental slope

e. a steady incline starting at the end of a continental shelfe. a steady incline starting at the end of a continental shelf

3. Seamount3. Seamount

b. mountain whose peak does not break through the surface of the b. mountain whose peak does not break through the surface of the ocean.ocean.

4. Abyssal plain4. Abyssal plain

f. broad flat area covered with thick layers of mud and siltf. broad flat area covered with thick layers of mud and silt

5. Volcanic island5. Volcanic island

d. a volcano on the ocean floor that creates a mountain big enough to d. a volcano on the ocean floor that creates a mountain big enough to break the ocean surface.break the ocean surface.

6. Mid-ocean ridge6. Mid-ocean ridge

a. consists of many peaks along both side of a central valley.a. consists of many peaks along both side of a central valley.

7. Trench7. Trench

g. a long, narrow, and deep depression with steep sides on the ocean g. a long, narrow, and deep depression with steep sides on the ocean floor.floor.

ContinentalShelf

Continental shelf

Continental slope

Continental slopeSeamount

Volcanic island

Continental rise Abyssal plain

mid-ocean ridge Rift valleytrench

ReviewReview1.1. With sonar, what happens to sound pulses from With sonar, what happens to sound pulses from

a ship after they hit the ocean floor?a ship after they hit the ocean floor?A: they bounce back to the shipA: they bounce back to the ship

2.2. What can scientist conclude the longer it takes What can scientist conclude the longer it takes sound to return to a ship?sound to return to a ship?A: the deeper the ocean floor is in that spotA: the deeper the ocean floor is in that spot

3.3. What are 4 ways that scientist study the ocean What are 4 ways that scientist study the ocean floor?floor?A: sonar, piloted vessels, robotic vessels and A: sonar, piloted vessels, robotic vessels and satellites.satellites.

4.4. What is a guyot?What is a guyot?A: flat-top seamountA: flat-top seamount

55. Where is the mid-ocean ridge located?. Where is the mid-ocean ridge located?A: Atlantic oceanA: Atlantic ocean