1. Unit 11 Lesson 2 How Does Ocean Water Move?
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2. Unit 11 Lesson 2 How Does Ocean Water Move?
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3. Catch a Wave A wave is the up-and-down movement of surface water.
Unit 11 Lesson 2 How Does Ocean Water Move?
Catch a Wave
A wave is the up-and-down movement of surface water.
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4. Catch a Wave Unit 11 Lesson 2 How Does Ocean Water Move?
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5. Catch a Wave Unit 11 Lesson 2 How Does Ocean Water Move?
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6. Unit 11 Lesson 2 How Does Ocean Water Move?
Catch a Wave
Surface waves are caused by wind pushing against the surface of the water.
Waves constantly affect the shoreline. Even gentle waves weather and erode rock and transport sand.
Powerful hurricane winds produce much larger waves, which can cause a storm surge, or an unusually high water level.
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7. Catch a Wave Unit 11 Lesson 2 How Does Ocean Water Move?
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8. Catch a Wave Unit 11 Lesson 2 How Does Ocean Water Move?
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9. Catch a Wave Energy in waves can be converted into electrical energy.
Unit 11 Lesson 2 How Does Ocean Water Move?
Catch a Wave
Energy in waves can be converted into electrical energy.
This electrical energy can provide a steady source of electricity, since wave motion never stops.
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10. Unit 11 Lesson 2 How Does Ocean Water Move?
Go with the Flow
An ocean current is a steady flow of water in a regular pattern in the ocean.
Steady winds
temperature
water salinity
the shape of both ocean floor and shoreline.
play a role in driving currents.
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11. Go with the Flow Ocean currents can have predictable effects.
Unit 11 Lesson 2 How Does Ocean Water Move?
Go with the Flow
Ocean currents can have predictable effects.
For example, the Gulf Stream is warm Atlantic Ocean water that runs south to north along the eastern coast of North America.
The warm Gulf Stream helps make weather in Europe warmer than in other places that are as far north.
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12. Go with the Flow Unit 11 Lesson 2 How Does Ocean Water Move?
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13. Unit 11 Lesson 2 How Does Ocean Water Move?
Go with the Flow
Water steadily flowing from the shore against incoming waves is called a rip current.
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14. Go with the Flow Unit 11 Lesson 2 How Does Ocean Water Move?
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15. Unit 11 Lesson 2 How Does Ocean Water Move?
Go with the Flow
Sometimes, water in the South Pacific gets unusually warm, producing a climate pattern called El Niño.
An El Niño season disrupts normal weather patterns, causing extreme weather, such as droughts and flooding throughout the world.
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16. Go with the Flow Unit 11 Lesson 2 How Does Ocean Water Move?
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17. The Turning Tides Unit 11 Lesson 2 How Does Ocean Water Move?
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18. Unit 11 Lesson 2 How Does Ocean Water Move?
The Turning Tides
The water level of the ocean rises and falls in a cycle called a tide.
Tides are caused by the “pull” of the sun and moon on Earth’s oceans.
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19. Unit 11 Lesson 2 How Does Ocean Water Move?
The Turning Tides
The moon’s gravity pulls on Earth, resulting in two bulges forming in Earth’s oceans.
The higher water level in the bulges produces a high tide. The lower water level, or low tide, occurs between the bulges.
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20. Unit 11 Lesson 2 How Does Ocean Water Move?
The Turning Tides
When Earth, the sun, and the moon are in a straight line, their combined gravity causes the highest high tides and the lowest low tides.
When the sun, Earth, and the moon are positioned in an “L” shape, the difference between the levels of high tide and low tide is the smallest.
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21. Unit 11 Lesson 2 How Does Ocean Water Move?
The Turning Tides
The relative positions of the sun, moon, and Earth affect the heights of tides.
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22. The Turning Tides Unit 11 Lesson 2 How Does Ocean Water Move?
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23. The Turning Tides Unit 11 Lesson 2 How Does Ocean Water Move?
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24. Changing Shorelines Land at the edge of the ocean is called shore.
Unit 11 Lesson 2 How Does Ocean Water Move?
Changing Shorelines
Land at the edge of the ocean is called shore.
Waves and ocean currents carry sand to and away from the shore. The same wind that drives the waves also causes rocks and cliffs to weather.
The ocean can carry sand from beaches in a short time. A big storm can erode a beach in a day.
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25. Unit 11 Lesson 2 How Does Ocean Water Move?
Changing Shorelines
People can restore the beach by replacing and stabilizing the sand and by building structures.
A jetty is a structure, often made of piles of rock, that a current cannot move.
Jetties preserve beaches and keep sand from accumulating and making waterways too shallow for boats.
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26. Changing Shorelines Unit 11 Lesson 2 How Does Ocean Water Move?
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27. Unit 11 Lesson 2 How Does Ocean Water Move?
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