Concept Block Three: Landforms and Oceans
I. In this section we will concentrate on the following standard and its components:
Standard: 5Sc: The student will demonstrate an understanding of features, processes, and changes in Earth’s land and oceans. (Earth Science)
5Sc.1: Explain how natural processes (including weathering, erosion,
deposition, landslides, volcanic eruptions, earthquakes, and floods)
affect Earth’s oceans and
land in constructive and destructive ways.
5Sc.2: Illustrate the geologic landforms of the ocean floor (including the
continental shelf and slope, the mid-ocean ridge, rift zone, trench, and
the ocean basin).
5Sc.3: Compare continental and oceanic landforms.
5Sc.4: Explain how waves, currents, tides, and storms affect the geologic
features of the ocean shore zone (including beaches, barrier islands,
estuaries, and inlets).
5Sc.5: Compare the movement of water by waves, currents, and tides.
5Sc.6: Explain how human activity (including conservation efforts and
pollution) has
affected the land and the oceans of Earth.
II. These concepts correspond to the following sections in the Scott Foresman Textbook:
1) C21-C27, What Changes the Earth’s Surface?
2) C28-29, Investigating Weathering (Activity)
3) C30-C32, How Rocks Change Form
4) C42, Exploring the Earth’s Resources (Activity)
5) C43-C67, Resources
6) C68-C69, Investigating Air Pollution (Activity)
7) C92-C93, Ocean Currents
III. These concepts are encountered in the following Reading Street stories and articles:
1) Adapting Lagoon (Unit 4)
2) The unsinkable Wreck of the Titanic (Unit 5)
3) Shipwreck Season (Unit 5)
4) Journey to the Center of the Earth (Unit 5)
5) Crust, Mantle, Core (unit 5)
6) Ghost Towns of the West (Unit 5)
7) Dame Shirley Goes to the Gold Rush (Unit 5)
IV. Concept Block Three: Concept Summary
Standard: 5Sc: The student will demonstrate an understanding of features, processes, and changes in Earth’s land and oceans. (Earth Science)
5Sc.1: Explain how natural processes (including weathering, erosion,
deposition, landslides, volcanic eruptions, earthquakes, and floods)
affect Earth’s oceans and land in constructive and destructive ways.
Content Summary:
· It is important for students to recognize that Earth is a closed system. With the exception of sunlight and the occasional meteorite, nothing enters the Earth, and nothing leaves. Therefore, any changes that occur on Earth are strictly “in house”. What happens on Earth stays on Earth. Most of these changes occur regularly and repeatedly, in cycles. The Earth recycles everything it has; water, nutrients, oxygen, etc. The Earth even recycles itself. It is dynamic. It forms and reforms rocks (the rock cycle), and it is constantly reforming its surface features, both above and below water. It accomplishes this through a number of natural processes.
· Weathering is the process that breaks down and changes rocks. As the name implies, these changes are brought on by weather. Rain, wind, flooding, drought, frost, and heat can cause weathering. Wave action also breaks down a lot of rocks. Just look at all the sand at the beach…
· Erosion (to erode) involves the moving of weathered rock and soil. Wind can cause erosion as it blows loose sand and soil around. Water creates a great deal of erosion. Flowing water loosens rock and soil and conveys it from one place to another. The sides of rivers are often steep because the river is cutting through the surface, conducting soil and rock downstream as it goes. The Grand Canyon is an extreme example of this.
· Deposition (to deposit) is the dropping of materials moved by erosion. Swift moving water loosens soil and rock and carries it downstream, suspended in its mix. Once the water slows down, gravity causes these suspended particles to drop and settle forming layers of transported matter. Most wetlands and estuaries are created from material that was deposited in this way. The Louisiana delta contains soil that used to be Minnesota farmland! The wind can also create deposition. Sand dunes are created as the wind shifts loose particles around.
· Natural occurrences like earthquakes, volcanoes, and floods also create significant changes in the Earths features. A volcano for example can construct new land as it spews molten rock on to the surface. This can create new mountains, or islands. Earthquakes and floods tend to be destructive forces. They often breakdown existing areas and can cause a great deal of damage. However, earthquakes can raise the land where plates meet, and floods can add add soil and debris to wetlands.
5Sc.2: Illustrate the geologic landforms of the ocean floor (including the
continental shelf and slope, the mid-ocean ridge, rift zone, trench, and
the ocean basin).
· The Ocean Floor is land. It just happens to be covered by water. The easiest way to envision the ocean floor is to imagine it as if was drained. If we do that, we see the same landforms we are familiar with. There are mountains, valleys, plains, and canyons. They may have different names, but they are essentially the same.
· The Continental Shelf is the underwater part of a continent. It is the relatively shallow area off shore. As the shelf ends it gradually gets deeper and deeper. This transitional area is known as the continental slope. At times in the Earth’s history, the continental shelf has been above water.
· The Mid Ocean Ridge is actually a series of mountain ranges that stretch along the ocean floor. They may be below water, but they are
larger than the Rocky Mountains, and have the highest peaks in the world.
· Rift Zones are formed between tectonic plates. They are areas with deep cracks and fissures that form as plates pull apart from each other. When two friends fight, it sometimes forma a rift between them and they pull apart. When two plates separate they do the same thing.
· Ocean Trenches are deep underwater canyons. Trenches can be miles deep cracks in the ocean floor. They are extremely dark and contain unique organisms that are adapted for life in harsh environments. The ocean trenches are the least explored areas on earth.
· All of these features are found on the ocean floor in a general area called an ocean basin. The basin holds the oceans water, just as a bath tub is a basin that holds bath water.
5Sc.3: Compare continental and oceanic landforms.
· As previously mentioned, the Ocean Floor is land that just happens to be covered by water. If the area that you currently live in was to fill with water, most of its features would remain, it would just be underwater. The mountains, plains, and valleys around you would become ridges, shelves, and trenches (see 5Sc2).
5Sc.4: Explain how waves, currents, tides, and storms affect the geologic
features of the ocean shore zone (including beaches, barrier islands,
estuaries, and inlets).
· As described above (5Sc1), the action of waves and storms can have a great effect on coastal areas, causing weathering, erosion, and deposition of rocks and soil. Coupled with the action of water currents, these processes are constantly reshaping our coasts, building, removing, and building again.
· Beaches are created as a result of a number of geological processes, most significantly, wave action. Waves are formed as a result of the changing effects of the gravitational attraction between the earth and the moon. Waves carry a great deal of energy. This energy slowly wears away the rocks that form the shore line. Erosion breaks rocks apart and they become smaller and smaller until they are sand. This sand is deposited and shifts constantly.
· Barrier Islands are found around the world but are most common along the east coast of the U.S.A. They are long thin, sandy islands that located just off the main coast. Barriers islands are separated from the mainland by sections of water called sounds. These islands are separated from each other by sections of water called inlets. Barrier islands are popular places for vacations. They help protect the mainland from storm damage, and provide habitat for many creatures.
Barrier Islands off Maryland Coast Source: Howatuffworks.com
· Estuaries are places where rivers meet the sea. They are transitional areas with unique organisms. They are important breeding grounds for many fish. Estuaries have a mix of fresh and salt water (brackish water). The land around estuaries is built from soil deposited from upstream. Estuaries usually support large wetland areas. These wetlands are important for the survival of many bird species, and are important in controlling storm damage.
5Sc.5: Compare the movement of water by waves, currents, and tides.
· This one is a little tricky. Currents and tides move water, waves do not.
o Ocean currents are created primarily due to the interaction between warm and cold water. When warm and cold water meet, warm water tries to ride up over the cold water it encounters. The cold water in turn heads under the warm water. This interaction causes water to move in currents. The East Australian Current (EAC) made famous in the movie Finding Nemo is a great example. It moves warm water down the east coast of Australia, and is frequently ridden by marine creatures like sea turtles.
o Tides are created because the Moon is involved in a tug –o-war with the Earth. The Earth, with its greater gravitational pull, keeps the moon firmly in its orbit, but the moon also pulls at the earth. It pulls hard enough that it can actually pull the water in the ocean toward it a little bit. The water actually mounds up on the side of the Earth closest to the moon, as the moon strains to pull it away. This takes a bit of water away from the oceans in other areas. This is the basis of the tides. The side closest to the moon experiences high tide while the side farthest away has low tide. This situation reverses itself as the earth rotates, so that every seaside area experiences both low and high tide regularly.
o Waves are a bit different. Waves are simply energy passing through water. When we see waves at the beach, they seem to be walls of water rushing toward the shore, but the water isn’t doing much moving. Water molecules do bump in to each other as they pass the energy along, but they pretty much stay where they are. Notice that boats on rough seas bob up in down in the water, but they don’t fly along horizontally in the direction of the wave. Try it in the tub. A shampoo bottle will float in water. Push a little water toward it and a wave will form. You will see the bottle bob up and down, but it will stay in the same general area where you put it.
5Sc.6: Explain how human activity (including conservation efforts and
pollution) has affected the land and the oceans of Earth.
· About 71% of the Earth is covered by ocean. Less than 30% of the Earth is above water, yet we land dwellers have a very negative effect on the undersea world. Here are a few examples:
o Overfishing- We are currently harvesting more fish from the ocean than the ocean can replace. This is disrupting aquatic food webs and harming aquatic ecosystems.
o Pollution- When we dump foreign substances into the ocean we can cause a lot of damage. Oil spills for example coat and kill wildlife; detergents and other substances can cause algae to grow so well that they choke off light and oxygen to other creatures. Fishing nets and debris can ensnare and trap animals.
· Many people and countries are participating in conservation efforts to counter the negative impact we have on the ocean. The United States for example has passed laws limiting fishing, and preventing the hunting of whales. We also have programs to cut down on erosion and pollution, but we still have a long way to go before we get to a point where we balance our needs with the needs of the sea.
III. Suggested Resources:
The following sites provide activities and ideas in support of the above standards. Some can be used as is; others may need to be leveled for use in the fifth Grade classroom. All of them can be used as references to provide ideas for assisting your instruction.
5Sc.1: Explain how natural processes (including weathering, erosion,
deposition, landslides, volcanic eruptions, earthquakes, and floods)
affect Earth’s oceans and
land in constructive and destructive ways.
http://earthquake.usgs.gov/learn/kids/
http://www.eduplace.com/kids/sla/6/volcanoes.html
http://sciencespot.net/Pages/kdzethsci2.html
http://environment.nationalgeographic.com/environment/natural-disasters
http://www.kidskonnect.com/subjectindex/15-educational/science/92-natural- disasters.html
5Sc.2: Illustrate the geologic landforms of the ocean floor (including the
continental shelf and slope, the mid-ocean ridge, rift zone, trench, and
the ocean basin).
http://www.pitara.com/discover/earth/online.asp?story=126
http://www.education.noaa.gov/socean.html
5Sc.3: Compare continental and oceanic landforms.
http://www.kidsgeo.com/geology-for-kids/0039-sima-oceanic-crust.php
http://www.kidsgeo.com/geology-for-kids/0031-what-are-landforms.php
5Sc.4: Explain how waves, currents, tides, and storms affect the geologic
features of the ocean shore zone (including beaches, barrier islands,
estuaries, and inlets).
http://www.kidsgeo.com/geology-for-kids/0059-introduction-to-erosion.php
http://scienceforkids.kidipede.com/geology/rocks/sedimentary/erosion.htm
5Sc.5: Compare the movement of water by waves, currents, and tides.
http://www.ducksters.com/science/earth_science/ocean_waves_and_currents.php
http://www.virtualnjshore.com/tbwaves.html
5Sc.6: Explain how human activity (including conservation efforts and
Pollution) affected the land and the oceans of Earth.
http://www.buzzle.com/articles/ocean-pollution-facts.html
http://eschooltoday.com/pollution/water-pollution/what-is-water-pollution.html
http://water.epa.gov/learn/kids/waterkids/kids.cfm