1. Bellringer
Make sure you record today’s date, the question and your answer.
If there were no land on Earth’s surface, what would the pattern of surface currents look like? Explain your answer.

2. 3.1 Currents

3. Objectives: Describe surface currents.
List the three factors that control surface currents.
Describe deep currents.
Identify the three factors that form deep currents.

4. Introduction
Ocean current- ocean water that contains streamlike movements of water.
Ocean currents are influenced by a number of factors: weather, Earth’s rotation & position of continents.
With knowledge of currents, we can make predictions of where objects will float.

5. One Way to Explore Currents
Thor Heyerdahl’s Journey: Thor Heyerdahl’s completed a long ocean journey to prove his theory that ocean currents carried the ancient Peruvians across the Pacific to Polynesia.

6. Surface Currents
Surface current- a horizontal movement of ocean water that is caused by wind and that occurs at or near the ocean’s surface. Example: Gulf Stream
Controlled by:
Global Winds
Coriolis Effect
Continental Deflection

7. Global Winds
Different winds cause surface currents to flow in different directions.
In much the same way that you create ripples, winds that blow across Earth’s surface create surface currents in the ocean
Near the equator winds blow east to west and near the poles it is west to east

8. The Coriolis Effect
The Earth’s rotation causes wind and surface currents to move in curved paths rather than in straight lines.
It causes surface currents in the Northern Hemisphere to turn clockwise, and in the Southern Hemisphere to turn counterclockwise.

9. Continental Deflection
When surface currents meet continents, the currents deflect, or change direction.

10. Taking Temperatures
Both warm-water and cold-water currents travel from one ocean to another.

12. Deep Currents
Deep Ocean Currents- streamlike movements of ocean water located far below the surface are called deep currents.
Factors that form Deep Ocean Currents are:
Temperature
Salinity
Density

13. Formation & Movement of Deep Currents
Deep Ocean Currents- streamlike movements of ocean water located far below the surface are called deep currents.
Differences in temperature and salinity— and the resulting differences in density— cause variations in the movement of deep currents. The next slide shows how deep currents are formed.

14. How Deep Currents Form

15. Polar Regions
The warmer, less-dense water in surface currents cools and becomes the colder, denser water in deep ocean currents.