1. The Oceans The Big Idea Earth’s Waters What are the causes of waves, currents, and tides?

2. Exploring the Ocean People have studied the ocean since ancient times, because the ocean provides food and serves as a route for trade and travel. People have studied the ocean since ancient times, because the ocean provides food and serves as a route for trade and travel. Modern scientists have studied the characteristics of the ocean’s waters and the ocean floor. Modern scientists have studied the characteristics of the ocean’s waters and the ocean floor.

3. Exploring the Ocean The Phoenicians, who lived along the Mediterranean Sea, were one of the earliest cultures to explore the oceans. The Phoenicians, who lived along the Mediterranean Sea, were one of the earliest cultures to explore the oceans. They had established sea routes for trade with other nations around the Mediterranean by about 1200 b.c. They had established sea routes for trade with other nations around the Mediterranean by about 1200 b.c. Their knowledge of winds and currents enabled the Polynesians to settle the widely scattered islands of Hawaii, Tahiti, and New Zealand. Their knowledge of winds and currents enabled the Polynesians to settle the widely scattered islands of Hawaii, Tahiti, and New Zealand.

4. Exploring the Ocean 1700s, Captain James Cook lead three voyages of exploration. 1700s, Captain James Cook lead three voyages of exploration. Cook’s crew included scientists who studied the stars and those who collected new species of plants and animals. Cook’s crew included scientists who studied the stars and those who collected new species of plants and animals. The Challenger expedition marked the beginning of the modern science of oceanography. The Challenger expedition marked the beginning of the modern science of oceanography.

5. Exploring the Ocean Studying the ocean floor is difficult because the ocean is so deep – 3.8 kilometers deep on average, more than twice as deep as the Grand Canyon. Studying the ocean floor is difficult because the ocean is so deep – 3.8 kilometers deep on average, more than twice as deep as the Grand Canyon. First, because sunlight does not penetrate far below the surface, the deep ocean is in total darkness. First, because sunlight does not penetrate far below the surface, the deep ocean is in total darkness. Second, the water is very cold. Second, the water is very cold. Finally, deep ocean water exerts tremendous pressure due to the mass of water pushing down from above. Finally, deep ocean water exerts tremendous pressure due to the mass of water pushing down from above.

6. Exploring the Ocean Humans cannot survive the darkness, cold temperatures, and extreme pressure of the deep ocean. Humans cannot survive the darkness, cold temperatures, and extreme pressure of the deep ocean. A major advance in ocean-floor mapping was sonar, which stands for sound navigation and ranging. A major advance in ocean-floor mapping was sonar, which stands for sound navigation and ranging. Sonar is a system that uses sound waves to calculate the distance to an object. Sonar is a system that uses sound waves to calculate the distance to an object.

8. Exploring the Ocean If you could travel along the ocean floor, you would see the continental shelf, the continental slope, and the abyssal plain, and the mid-ocean ridge. If you could travel along the ocean floor, you would see the continental shelf, the continental slope, and the abyssal plain, and the mid-ocean ridge.

9. Exploring the Ocean

10. Shallow Water Shallow Water As you leave the harbor, your submarine first passes over a section of the ocean floor called the continental shelf. As you leave the harbor, your submarine first passes over a section of the ocean floor called the continental shelf. Gently sloping, shallow area of the ocean floor extends outward from the edge of a continent. Gently sloping, shallow area of the ocean floor extends outward from the edge of a continent. The incline beyond the edge of the continental shelf called the continental slope. The incline beyond the edge of the continental shelf called the continental slope.

11. Exploring the Ocean Open Ocean Open Ocean Mountains, called seamounts, are completely underwater. Mountains, called seamounts, are completely underwater. Abyssal plains, a smooth, nearly flat region of the ocean floor are a broad area covered with thick layers of mud and silt. Abyssal plains, a smooth, nearly flat region of the ocean floor are a broad area covered with thick layers of mud and silt.

12. Exploring the Ocean The mid-ocean ridge is made up of a range of mountains that winds through the oceans, much as the line of stitches winds around a baseball. The mid-ocean ridge is made up of a range of mountains that winds through the oceans, much as the line of stitches winds around a baseball.

13. Exploring the Ocean Deepest Depths Deepest Depths A trench is a canyon in the ocean floor. The trench is so deep you cannot see the bottom. A trench is a canyon in the ocean floor. The trench is so deep you cannot see the bottom.

15. Exploring the Ocean A – Continental Slope – a steady incline marks the continental slope. Continental slopes in the Pacific Ocean are steeper than those in the Atlantic Ocean. A – Continental Slope – a steady incline marks the continental slope. Continental slopes in the Pacific Ocean are steeper than those in the Atlantic Ocean. B – Seamount – Mountains whose peaks do not break the surface of the ocean water above them. B – Seamount – Mountains whose peaks do not break the surface of the ocean water above them.

16. Exploring the Ocean C – Abyssal Plain – thick layers of sediment, formed by the sunken remains of dead organisms from the surface, cover these vast, flat plains. C – Abyssal Plain – thick layers of sediment, formed by the sunken remains of dead organisms from the surface, cover these vast, flat plains. D – Mid-Ocean Ridge – consists of many peaks along both sides of a central valley. This chains of undersea mountains runs all around the world. D – Mid-Ocean Ridge – consists of many peaks along both sides of a central valley. This chains of undersea mountains runs all around the world.

17. Exploring the Ocean E – Volcanic Island – when volcanoes on the ocean floor erupt, they can create mountains whose peaks break the surface of the ocean. As the lava cools, islands form. E – Volcanic Island – when volcanoes on the ocean floor erupt, they can create mountains whose peaks break the surface of the ocean. As the lava cools, islands form. F – Continental Shelf – this gradually sloping area borders, each continent. Its width varies from just a few kilometers to as much as 1,300 kilometers. F – Continental Shelf – this gradually sloping area borders, each continent. Its width varies from just a few kilometers to as much as 1,300 kilometers.

18. Exploring the Ocean G – Trenches – canyons include Earth’s deepest points. The Marina Trench in the Pacific is 11 kilometers deep. G – Trenches – canyons include Earth’s deepest points. The Marina Trench in the Pacific is 11 kilometers deep.

19. Exploring the Ocean Ocean Zones Ocean Zones The ocean into zones. The ocean into zones. Ocean zones includes Ocean zones includes Intertidal Zone Intertidal Zone Neritic Zone Neritic Zone Open-Ocean Zone Open-Ocean Zone

20. Exploring the Ocean Intertidal Zone Intertidal Zone Begins at the highest high-tide line. Begins at the highest high-tide line. Stretches out to the point exposed by the lowest low tide. Stretches out to the point exposed by the lowest low tide. Neritic Zone Neritic Zone Extends from the low-tide line out to the edge of the continental shelf. Extends from the low-tide line out to the edge of the continental shelf.

21. Exploring the Ocean Open-Ocean Zone Open-Ocean Zone This zone include the deepest, darkest part of the ocean. This zone include the deepest, darkest part of the ocean. The physical conditions of each ocean zone help determine which organisms can live that zone. The physical conditions of each ocean zone help determine which organisms can live that zone.

22. Wave Action What Is a Wave? What Is a Wave? The movement of energy through a body of water. The movement of energy through a body of water. Development usually begins with wind. Development usually begins with wind. Most waves form when winds blowing across the water’s surface transmit their energy to the water. Most waves form when winds blowing across the water’s surface transmit their energy to the water.

23. Wave Action Wave Size Wave Size Waves start in the open ocean Waves start in the open ocean Depends on the strength of the wind and on the length of time it blows. Depends on the strength of the wind and on the length of time it blows. Size of a wave also depends on the distance over which the wind blows. Size of a wave also depends on the distance over which the wind blows.

24. Wave Action Wave Energy Wave Energy Energy of the wave move toward shore, but the water itself remains in place. Energy of the wave move toward shore, but the water itself remains in place. Although waves may appear to carry water toward shore, the water does not actually move forward in deep water. Although waves may appear to carry water toward shore, the water does not actually move forward in deep water.