Science Fusion PowerNotes - Grade 8 Unit 3 Lesson 5 - Ocean Currents

1. Unit 3 Lesson 5 Ocean Currents
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2. Unit 3 Lesson 5 Ocean Currents
Indiana Standards
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• 8.2.1 Recognize and demonstrate how the sun’s
energy drives convection in the atmosphere and in
bodies of water, which results in ocean currents
and weather patterns.
• 8.2.3 Describe the characteristics of ocean
currents and identify their effects on weather
patterns.

3. Going with the Flow
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What are ocean currents?
• Ocean currents are streamlike movements of
water in the ocean.
• Surface currents are ocean currents that occur
at or near the surface of the ocean.
• The Gulf Stream is a surface current.
Unit 3 Lesson 5 Ocean Currents

4. What affects surface currents?
• Surface currents are affected by continental
deflections, the Coriolis effect, and global winds.
• When surface currents meet continents, they are
deflected and change direction.
• The deflection of moving objects from a straight
path due to Earth’s rotation is the Coriolis effect.
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Unit 3 Lesson 5 Ocean Currents

5. What affects surface currents?
• How does a continent change surface currents on
Earth? Could a small island change surface
currents?
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Unit 3 Lesson 5 Ocean Currents

6. What affects surface currents?
• In the Northern Hemisphere, currents are
deflected to the right.
• In the Southern Hemisphere, currents are
deflected to the left.
• Global winds can push ocean water across Earth’s
surface to create surface currents.
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Unit 3 Lesson 5 Ocean Currents

7. What powers surface currents?
• The major source of energy that powers surface
currents is the sun.
• The sun causes differences in temperature across
Earth, which causes differences in air pressure.
• Winds form as a result of differences in air
pressure and create surface currents.
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Unit 3 Lesson 5 Ocean Currents

8. Current Events
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How do deep currents form?
• Deep currents are movements of ocean water
below the surface caused by differences in density.
• Density is the amount of matter in a given space or
volume.
• Salinity and temperature cause differing ocean
water densities.
Unit 3 Lesson 5 Ocean Currents

9. How do deep currents form?
• Salinity is a measure of the amount of dissolved
salts or solids in a liquid.
• Higher salinity makes water more dense.
• Dense water sinks and can form deep water
currents that flow along the ocean floor or on
another layer of denser water.
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Unit 3 Lesson 5 Ocean Currents

10. What are convection currents?
• Convection currents in the ocean are the
movement of water that results from density
differences.
• Convection currents can be vertical, circular, or
cyclical.
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Unit 3 Lesson 5 Ocean Currents

11. How do convection currents transfer
energy?
• Water at the ocean’s surface absorbs energy from
the sun, which can be carried to colder regions.
• As water reaches a colder region, it cools and
sinks.
• As warm water moves away, cold water can rise
from the bottom of the ocean, and the cycle
continues.
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Unit 3 Lesson 5 Ocean Currents

12. That’s Swell
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What is upwelling?
• Upwelling is the process in which winds blow
warm water away from a shore, allowing cool,
nutrient-rich water to rise to the surface.
• Upwelling supplies the nutrients necessary for
ocean life to grow.
Unit 3 Lesson 5 Ocean Currents

13. What is upwelling?
• What would happen to ocean life if upwelling did
not occur?
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Unit 3 Lesson 5 Ocean Currents

14. Unit 3 Lesson 5 Ocean Currents
Hitchin’ a Ride
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• Ocean currents can carry life to other regions of
Earth.
• Turtles, coconuts, and phytoplankton all ride
surface currents in the ocean.

15. Traveling the World
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What do ocean currents transport?
• Convection currents in the ocean transport energy
in the form of heat.
• Ocean currents can release energy into the
atmosphere, making currents an important
influence on climate.
• Ocean water also transports solids, nutrients, and
gases to new locations.
Unit 3 Lesson 5 Ocean Currents

16. What do ocean currents transport?
• Trace a path on the map to show how nutrients
are transported around Earth.
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Unit 3 Lesson 5 Ocean Currents