Transcript ESS 8.8.2
GLOBAL WATER CURRENTS
8 TH GRADE SCIENCE ESS. 8.8.2
THE GULF STREAM
For as many years as ships have sailed, sailors have used surface currents to help them travel quickly.
During the american colonial era, ships floated on the 100 km wide gulf stream to go quickly from north america to england.
Ocean surface currents
An ocean current is like a river within the ocean. It moves masses of water from place to place.
Surface currents distribute heat from equatorial regions to other areas of earth.
Waters flowing away from the equator transfer heat to the atmosphere, which can influence climate.
Ocean surface currents
Surface ocean currents, like surface winds, are influenced by the coriolis effect.
The coriolis effect deflects currents north of the equator, such as the gulf stream, to the right.
Currents south of the equator are deflected to the left.
Ocean surface currents
On a world ocean current map, you will see that currents on the western coasts of continents are usually cold, whereas currents on eastern coasts are warm. Warm currents on eastern coasts originate near the equator.
vocabulary
1. coriolis effect – the effect of earth’s rotation (spin) on the movement of air and water masses. It changes the direction of air and water flow.
2. Gulf stream – an ocean current that flows out of the gulf of mexico, northward along the east coast of the u. s. and then towards europe.
vocabulary
3. surface currents – ocean currents powered by wind that move water horizontally, parallel to earth’s surface.
4. Climate – the pattern of weather in a particular area over a period of many years.
DIFFERENT LANDFORMS FOUND ON EARTH
8 TH GRADE SCIENCE
ESS.8.8.3
MOUNTAINS
There are 4 types of mountains.
FOLDED
UPWARPED
FAULT-BLOCK
VOLCANIC
FOLDED MOUNTAINS
Tremendous forces inside Earth force rock layers together. COMPRESSION is the force that squeezes rock layers together from opposite sides.
When rock layers are squeezed from opposite sides, they buckle and fold into FOLDED MOUNTAINS.
Technically, there are no mountains in Arkansas, but the “hills” in The Hot Springs area are folded.
The Appalachian mountains are folded mountains.
FOLDED MOUNTAINS
UPWARPED MOUNTAINS
The southern Rocky Mountains in Colorado and New Mexico, the Black Hills in South Dakota, and the Adirondak mountains in New York are UPWARPED MOUNTAINS.
UPWARPED MOUNTAINS
These mountains were formed when crust was pushed up by forces inside Earth.
Over time, the weaker sedimentary rock on top eroded, leaving behind the tougher igneous and metamorphic rock underneath. These igneous and metamorphic rocks then eroded to form sharp peaks and ridges.
FAULT-BLOCK MOUNTAINS
The Grand Tetons of Wyoming and the Sierra Nevada mountains in California formed in a different way.
FAULT-BLOCK mountains are made of huge tilted blocks of rocks that are separated from surrounding rocks by faults.
A FAULT is a large crack in rocks along which there is movement.
FAULT-BLOCK MOUNTAINS
When these mountains formed, one block was tilted and pushed up. The other block was pushed down.
Sharp, jagged peaks are characteristic of Fault-Block mountains.
VOLCANIC MOUNTAINS
Mount St. Helens in Washington and Mauna Loa in Hawaii are 2 of many volcanic mountains in the U. S.
Volcanic mountains form when molten material reaches the surface through a weak area of the crust.
The materials pile up, one layer on top of another, until a cone-shaped structure forms.
VOLCANIC MOUNTAINS
There are 2 types of volcanic eruptions, which will determine how a volcanic mountain looks.
QUIET ERUPTION – Caused by thin, runny lava called BASALTIC lava. The lava does not clog up the opening of the volcano and runs out forming a broad, domelike volcano called a SHIELD volcano. The Hawaiian islands were formed by quiet eruptions at HOT SPOTS.
MAUNA LOA - HAWAII
VOLCANIC MOUNTAINS
The other type of eruption is an EXPLOSIVE eruption.
An explosive eruption deals with thick, pasty GRANITIC magma.
The magma clogs up the volcano’s opening, or vent, and pressure builds up inside the volcano until it explodes. These types of eruptions form huge mountains with fairly steep slopes, or small steep sided volcanoes called CINDER CONES. Mount St. Helens is a COMPOSITE volcano, made up of alternating quiet and explosive eruptions.
MOUNT ST. HELENS
PLATEAUS
PLATEAUS are relatively flat, raised areas of land.
They are areas made up of nearly horizontal rocks that have been uplifted by forces within Earth.
An example of a plateau in the U. S. is the Colorado Plateau. The Colorado river has cut deeply into the rock layers of the plateau, forming the Grand Canyon.
COLORADO PLATEAU
BUTTE PLATEAU
OZARK PLATEAU
BUFFALO RIVER
BUFFALO RIVER
REVIEW
1. THE BUFFALO NATIONAL RIVER IS LOCATED IN WHAT PLATEAU?
OZARK 2. TYPE OF MOUNTAIN FORMED BY ERUPTIONS?
VOLCANIC 3. THE TYPE OF FORCES THAT PUSH TOWARD EACHOTHER?
COMPRESSION 4. THE TYPE OF FORCES THAT PULL AWAY FROM EACHOTHER?
TENSION
REVIEW
5. TYPE OF MOUNTAIN FORMED WHEN FORCES INSIDE EARTH LIFTS UP AN AREA OF LAND?
UPWARPED 6. TYPE OF MOUNTAIN FORMED BY FAULTING?
FAULT-BLOCK 7. TYPE OF MOUNTAIN FORMED BY COMPRESSION FORCES IN THE EARTH?
FOLDED 8. THE BLACK HILLS IN SOUTH DAKOTA ARE WHAT TYPE OF MOUNTAINS?
UPWARPED.
REVIEW
9. THE APPALACHIAN MOUNTAINS ARE WHAT TYPE?
FOLDED 10. MOUNT ST. HELENS AND MAUNA LOA ARE WHAT TYPE OF MOUNTAINS?
VOLCANIC
11. THE GRAND TETONS ARE WHAT TYPE OF MOUNTAINS?
FAULT BLOCK 12. THESE ARE RELATIVELY FLAT, RAISED AREAS OF LAND?
PLATEAUS
REVIEW
13. WHERE IS THE OZARK PLATEAU LOCATED?
NORTH ARKANSAS/SOUTHERN MISSOURI 14. THE COLORADO RIVER HAS CUT DEEPLY INTO THE COLORADO PLATEAU FORMING THE ?
GRAND CANYON 15. BASALTIC MAGMA IS ASSOCIATED WITH WHAT TYPE OF VOLANIC ERUPTION?
QUIET 16. WHAT TYPE OF MAGMA IS ASSOCIATED WITH EXPLOSIVE ERUPTIONS?
GRANITIC