5th grade Science Teacher Imarlys Cajigas Earth’s Oceans 5th grade Science Teacher Imarlys Cajigas

Lesson 1: What are the Oceans like? Vocabulary Salinity Water pressure Continental shelf Continental slope Abyssal plain Fast Fact: Some people believe that ocean water cannot freeze because it’s salt water. Does ocean water freeze at the same temperature as fresh water?

Ocean Water The salt in the ocean comes from minerals that are washed out from the land. Most of the salt is sodium chloride, table salt, but ocean water also has other salts. The amount of salt in water is called salinity.

Do you think that oceans have the saltiest water on Earth? The salinity of the Dead Sea, a lake in Israel, is ten times more than oceans. This is because less water flows into the Dead Sea than evaporates from it. (Increasing the salinity) Do you think that oceans have the saltiest water on Earth?

Characteristics of the Ocean About 90% of the ocean has a temperature between 0˚C and 3˚C. That’s cold! The ocean gets darker with depth, until there is no light at all. Something else that depends on the ocean’s depth is pressure. Water pressure increases as you go deeper into the ocean.

To study the oceans scientist use submarines called submersibles.

The Ocean Floor Continental shelf- extend from the edge of the continents to the ocean. Continental slope- drops steeply about 10,000 ft. below the surface. Continental rise- drops down about 13,000 ft. Abyssal Plain- the average depth is 15,000 ft. It can have mountain ridges, volcanoes, and deep trenches.

The Ocean Floor The ocean floor slopes down from the edges of the continents. Then it becomes mostly flat, though it also has mountains and other surface features. Deep canyons can be found in some parts of the continental shelf and continental slope.

The Ocean Floor The largest flattest area in the ocean is the abyssal plain. However, abyssal plains aren’t completely flat in some places they are cut by deep trenches.

The Mariana’s Trench is the deepest place on Earth with a depth of 11,035m (36,000 ft.)

Changes to the ocean floor The ocean floor is always changing. In 1963, an underwater volcano began to erupt for four years building up layers of lava, forming the island of Surtsey. Now Surtsey is getting smaller and sinking slightly. Ocean waves are wearing away the island.

Changes to the Ocean Floor Island in the ocean can disappear completely. Bora- Bora, an island in the Pacific ocean has been sinking. Coral reefs grew a ring around the island. In the future Bora-Bora will be gone and corals will still be there forming an island called atoll.

Lesson 2: How does Ocean Water move?

Vocabulary Wave Current Tide Fast Fact: When waves approach the shore, they seem to move in sets. In each set, the waves get bigger and bigger and then smaller and smaller again. Then, another set begins.

Waves A wave is the up-and-down movement of surface water. Energy from the moving air moves the water. A wave carries energy, not water, across the ocean. Inside the wave the water turns into small ovals. The energy travels forward. Water moves up and down and energy moves forward.

Waves As the water becomes shallow, the waves slow down. They also becomes higher and closer together. The biggest waves are not caused by wind, the great energy of earthquakes or volcanic eruptions can produce a wave called Tsunami. In the open ocean a Tsunami is not a high wave, but is long and moves very fast. As it reaches shore it slows down making the wave higher.

Currents Air around the equator is heated by the sun, this air moves north, toward the poles pushing the ocean water. The result is a current, a stream of water that flows like a river through the ocean. The Gulf Stream is a surface current that flows all the way across the Atlantic Ocean. It begins in the Gulf of Mexico and flows north along the eastern coast of US. Then, it turns east and flows across the Atlantic Ocean to Europe.

Currents Long-shore currents sometimes flow across the shore. It carries swimmers away from the place they entered the water. This is why sometimes people have trouble finding their towel and sandals. Rip-current carry water away from the beach, this makes them dangerous for swimmers. It can flow faster than 2.4m/sec. (faster that an Olympic swimmer can swim) Deep-ocean currents- carry cooler water up toward the surface near the coast. It is caused by differences in water temperature.

El Niño Is a change in the weather patterns over the Pacific Ocean. How does the warm water affect the weather? Warm water evaporates faster than cool water forming clouds and bringing rain. During El Niño Australia has very dry weather and North and South America get storms and huge amounts of rain.

Tides Each day the water level at an ocean shore rises and falls. The rise and fall in the water level of the ocean is called a tide. Tides are caused by the pull of the Sun and moon on Earth’s oceans. Although the Sun is larger, the moon affects tides more because it is closer to Earth. There are usually two high tides and low tides every day.

Tides The level of the ocean is higher in the bulges, producing high tides. In the part of the ocean between the bulges the water level is lower, a low tide occurs.