Warm Up 2/4

1. Warm Up 2/4 • Name the Earth’s four major ocean basins. • Pacific, Atlantic, Indian, and Arctic • Sediments that cover the ocean floor come from which of the following a. Life forms b. Land c. Water d. All of the above • What size of sediment will be found closer to the shore? • Large

2. The Vast World Ocean Chapter 14, Section 1

3. The Blue Planet • Nearly 71% of Earth’s surface is covered by the global ocean • It has only been since the late 1800s that the ocean became an important focus of scientific studies • Oceanography – a science that draws on the methods of geology, chemistry, physics and biology to study all aspects of the world ocean

4. The Blue Planet

5. Geography of the Oceans • The world ocean can be divided into four main ocean basins – the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, and the Arctic Ocean • The Pacific Ocean is the largest ocean and the largest geographic feature on Earth (deepest at an average depth ~ 3940 m) • The Atlantic Ocean is about half the size of the Pacific, and much more narrow • The Indian Ocean is slightly smaller than the Atlantic, but has about the same average depth • The Arctic Ocean is only about 7% the size of the Pacific and about ¼ as deep as the rest of the oceans

6. Geography of the Oceans

7. Concept Check • What are the four main ocean basins? • Pacific Ocean, Atlantic Ocean, Indian Ocean, and Arctic Ocean

8. Mapping the Ocean Floor • If all the water were drained from the oceans, we would see everything from chains of volcanoes, tall mountain ranges, trenches, and large submarine plateaus • The topography of the ocean floor is as diverse as that of continents • Bathymetry – the measurement of ocean depths and the charting of the shape or topography of the ocean floor • Today’s technology – particularly sonar, satellites, and submersibles – allows scientists to study the ocean floor in a more efficient and precise manner than ever before

9. Mapping the Seafloor

10. Sonar • Sonar is an acronym for sound navigation and ranging • It works by transmitting sound waves toward the ocean bottom • A sensitive receiver intercepts the echo reflected from the bottom • Then a clock precisely measures the time interval to fractions of a second • Depth can be calculated from the speed of sound in water and the time required for the energy pulse to reach the ocean floor and return

11. Sonar

12. Satellites • We can now measure the shape of the ocean floor from space with satellites orbiting Earth • Gravity attracts water towards regions where massive ocean floor features occur • This produces relative elevated areas on the ocean surface by mountains and ridges and depressions at canyons and trenches • Devices on satellites can measure variations in sea-surface height as small as 3-6 cm • Using this data and sonar data, scientists are creating detailed maps of the ocean floor

13. Satellites

14. Concept Check • How do satellites help us learn about the shape of the seafloor? • Satellites bounce microwaves off the ocean surface. Outgoing radar pulses are reflected back to the satellite and can be used to detect differences in sea surface height that can be correlated to seafloor features.

15. Submersibles • Submersible – a small underwater craft used for deep-sea research • They are used to collect data about areas of the ocean that were previously unreachable by humans • Most submersibles are unmanned and operated by computers

16. Submersibles

17. Cool Down • How does the area of Earth’s surface covered by the oceans compare with the area covered by land? • Nearly 71% of Earth’s surface is covered by oceans, 29% is covered by land • Why is deep-sea exploration and data collection difficult? • The deep ocean is a harsh environment for humans—cold, dark, and under high pressure. It is difficult to supply submersibles with power for continuous use. • What is one thing that you learned today that you never knew? Explain this new knowledge.

18. Assignment (Due 2/9) • Read Chapter 14 (pg. 394-413) • Do Chapter 14 Assessment #1-33 (pg. 417-418)