Unit 11 Lesson 2 How Does Ocean Water Move?
Catch a Wave A wave is the up-and-down movement of surface water.
Catch a Wave
Catch a Wave (wave effects) 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.
Catch a Wave
Catch a Wave
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.
Go with the Flow (What is current and what causes it?) 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.
Go with the Flow (Effects of currents) 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.
Go with the Flow Water steadily flowing from the shore against incoming waves is called a rip current.
Go with the Flow
Go with the Flow El Niño means The Little Boy, or Christ Child in Spanish. El Niño was originally recognized by fishermen off the coast of South America in the 1600s, with the appearance of unusually warm water in the Pacific Ocean.
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.
The Turning Tides
The Turning Tides (Definition - causes) 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.
The Turning Tides The relative positions of the sun, moon, and Earth affect the heights of tides.
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.
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.
The Turning Tides
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.
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.
Changing Shorelines