The Motions Of Our Oceans

The Motions Of Our Oceans Creating An Understanding Of…

Ocean CurrentsElement: d. Explain the causes of waves, currents, and tides.

GoalRewritten: Describe the reasons (sources) of waves, currents, and tides

• New Vocabulary Terms:

–Surface Current –Coriolis Effect–Deep Current–Upwelling–El Nino

Ocean Currents

The natural cycle of water movement throughout the oceans of the world.

Ocean CurrentsA current is a stream like movement of ocean water

Two types of currents areDeep Currents – are stream like movements of ocean water deep below the water surface

Are caused by

An increase in the density of ocean water

Which are caused by• Decreasing the…

Temperature: The polar, cold air causes water to become more dense, sink and become a deep current.• Increasing the…..Salinity:

1. Ocean Water freezes at the top. Water below does not freeze, becomes more dense, sinks and forms deep current.

2. Fresh water evaporates leaving saltier more dense water. The more dense water sinks and forms a deep current.

Two types of currents areSurface Currents are horizontal stream like movements of ocean water at or near the surface

Three factors controlling this type of current

• Global Winds – blow across the surface of the water and move the water in different directions based on wind direction

• Corriolis Effect – rotation of Earth causes the wind and currents to move in curved paths

• Continental Deflections – water in surface currents hits land and deflects (bounces off) and changes direction

This type of current is also affected by

• Temperature• Warm surface currents – form

near the equator and carry warm water to other parts of the ocean

• Cold surface currents – form near the poles and carry cold water to other parts of the ocean

Video

Summary1. Surface currents carry warm water from

other regions in the ocean to the poles.2. Warm water replaces the colder, denser

water that sinks to the ocean floor3. Deep currents carry colder, denser along

the ocean floor from polar regions to warmer regions

4. Water from deep currents replaces water leaving from the surface currents

Closing Think-Pair –Share

Explain the cause of currents.

• Why are currents important?• It was interesting to ________.• I understand _________________.• I don’t understand_____________.• It is important to remember ______.• Explain the relevancy of currents to your life

or how you might use this information while on vacation.