1. The picture below shows the triangle trade route in the 1500s
The picture below shows the triangle trade route in the 1500s. Why did ships sail in this clockwise direction?

2. The North Atlantic gyre (a current) moved ships in that direction
The North Atlantic gyre (a current) moved ships in that direction. It was easier to move with the current than against it.

3. Name the Earth’s Oceans!!!

4. Why 9 oceans and not 7?
The Atlantic and Pacific oceans are split into North and South because water in these regions follow a particular pattern and behavior.

5. What is a current?
A word that describes the movement of water

6. Two Types
Surface Currents
Deep Ocean Currents

7. Surface Currents
These are currents that are on the top layer of the ocean (up to several hundred meters deep).
They are caused mainly by the wind that occurs at the ocean’s surface.
They are also controlled by the Coriolis effect and continental deflections.

8. Global Winds Winds that blow across the Earth’s surface
The force of these winds move the water
Different winds cause currents to flow in different directions
Winds near the equator move east to west
Winds near the poles move west to east

9. Coriolis Effect
The apparent curving of the path of a moving object from an otherwise straight path due to the Earth's rotation.

10. Continental Deflection
If the earth’s Surface were covers completely in water, the currents would travel freely across the globe in a very uniform pattern.
Well we have huge land masses on our Earth called continents.
When surface currents meet
continents, the currents
deflect, or change direction.

11. Currents are Affected by Temperature
Warm-water currents begin near the equator and carry warm water to other parts of the ocean.
Cold-water currents begin closer to the poles and carry cold water to other parts of the ocean.

12. Gyres – A ring like system of ocean currents

13. Deep Ocean Currents
A stream like movement of water FAR below the surface.

14. Deep Ocean Currents
Cause = Formed in parts of the ocean where water density changes.
The density of the ocean water is affected by temperature and salinity
The colder the water is…the more dense
The more salt in the water… the more dense the water is

15. Deep Ocean Currents
Denser (Colder and higher salinity levels) water sinks!

16. How this works…
Surface currents carry the warmer, less-dense water from other ocean regions to the poles.
Once the temperature gets colder and the salinity levels increase, the water becomes more dense and sinks
Deep ocean currents carry the cold, dense water across the ocean floor from polar regions to other regions in the ocean
Once the water warms and its salinity levels decrease, it becomes less dense and rises.