Warm-up January 30

Name a physical featureon dry land that is similarto the Mid-Ocean Ridge.

Volcanoes, Mountains, Trenches

MYP Unit Question: How do we use water?

Area of Interaction: Health and Social Education

Learner Profile: Thinker and Balanced

Standard: Recognize the significant role of water in the Earth’s processes.

Learning Standard: I’m learning about currents because they move water throughthe oceans.

Opening: Ocean waves and currents video

Work Session: Notes on Currents (foldable)

Closing: Partner Questions

Currents

stream-like movements of waterWhat are currents?

If it’s written in BLUE, write it down.

There are two types of currents:Surface Currents (near the surface)

Deep Currents (deep in the ocean)

No, you DON’T have to write this, it’s not written in BLUE.

Surface Currents Warm surface

currents flow from the equator to poles.

Cold surface currents flow from the poles toward the equator.STOP!! If you think about

it, it makes sense: Hot at equator and cold at poles

Surface Currents Controlled by three factors: 1. global winds 2. the Coriolis effect3. location of the

continents

Gulf Streamone of the longest surface currents—it transports 25 times more water than all the rivers in the world.

Some of the Aleutian Islands of Alaska are at the same latitude as England. Why would England’s climate be much warmer?

What if… What if you

made a raft out of balsa wood and tried to sail it from Peru to Indonesia?You would

eventually get there. The ocean currents and wind would move the raft.(Approx. 6000 miles)

Global winds• equator, winds blow east to west• poles, winds blow west to east

Trade WindsMerchants would“catch the wind”To assist them intheir trading.

Horse LatitudesAn area where the wind doesn’t blow

Coriolis EffectThe Earth’s rotation causes wind and surface currents to move in curved paths rather than in straight lines. The apparent curving of moving objects from a straight path due to the Earth’s rotation is called the Coriolis effect

Northern Hemisphere turns clockwise Southern Hemisphere turn counterclockwise.

Location of the ContinentsWhen surface currents meet continents, the currents deflect, or change direction.

Deep-Ocean Currents• located far below the surface• forms in denser ocean water (more salt)

• density depends on temperature and salinity.

DEEP CURRENTS Caused by water of different

densities Warm water rises: Cooler water sinks Salty water sinks, less salty water rises

Water sinksWater Cools

Or

Salinity Increases

Water Warms

Or

Salinity DecreasesWater

rises

DEEP CURRENTS MOVE VERTICALLY

UpwellingThe process in which cold

nutrient-rich water from the deep ocean rises to replace warm surface water

Very important to tiny organisms like plankton. Fish and birds feed on these organisms.

Upwelling

El NinoExtra large waves

caused by upswellings.

Occurs every 2-7 years

Begins when an unusual pattern of winds forms over the western Pacific.

Warm water moves east.

Closing: Partner Questions

Turn to the person on your right (or

left if necessary) and ask them a question about something you learned today.

Do they know the answer?? If not, share the answer with them.