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Sometimes very cold air can blow over
the ocean and or large bodies of water
like lakes. In certain cases the water
may be warmer than the air. As the cold
air passes over warm water, it picks up
moisture. When the air reaches land it
begins to rise.
Based on this information, what type of
weather could form over the land?
Do Now
Which way do the surface
currents flow in the northern
hemisphere? In the southern
hemisphere?
Objectives
Describe
and identify factors that
form and control deep and
surface currents.
Explain how currents affect
climate
Agenda
 Today
we will:
Day
1
Complete
Take
notes from teacher presentation.
Day
2
Complete
Exit
a do now.
a group activity.
ticket.
Vocabulary
Ocean
current
Surface current
Deep current
Upwelling
Currents
• Ocean water contains streamlike
movements of water called ocean
currents.
Surface Currents
• Horizontal, streamlike movements of
water that occur at or near the surface of
the ocean are called ocean currents.
• Surface currents are controlled by three
factors: global winds, the Coriolis effect,
and continental deflections.
Surface Currents, continued
• Global Winds Winds that blow across the
Earth’s surface create surface currents in the
ocean. Different winds cause currents to flow
in different directions.
• The Coriolis Effect is the apparent curving
of moving objects from a straight path due to
the Earth’s rotation.
The Coriolis Effect
Click below to watch the Visual Concept.

E:\~~2014-2015 Lesson Plans\7th Grade\Unit 3\MS-ESS2-6 Ocean
Currents\H3\80215.html
Surface Currents, continued
• Continental Defections When surface currents
meet continents, the currents deflect, or change
direction.
Surface Currents, continued
• Taking Temperature Currents are also
affected by the temperature of the water in
which they form.
• The next slide shows Earth’s surface
currents. Warm-water currents are shown as
red arrows, and cold-water currents are shown
as blue arrows.
Deep Currents
• Streamlike movements of ocean water
located far below the surface are called deep
currents. Deep currents are not controlled by
wind.
• Deep currents form in parts of the ocean
where water density increases. The density of
the ocean is affected by temperature and
salinity.
Deep Currents, continued
• Formation and Movement of Deep
Currents Differences in water density
cause variations in the movement of
deep currents.
Surface Currents and Climate
• Warm-Water Currents and Climate
Warm-water currents create warmer
climates in coastal areas that would
otherwise be much cooler.
Surface Currents and Climate, continued
• Cold-Water Currents and Climate
Cold-water currents keep climates along
a coast cooler than the inland climate
year-round.
Surface Currents and Climate, continued
• Upwelling is the movement of deep, cold, and
nutrient-rich water to the surface of the ocean.
• The nutrients that are brought to the surface
support the growth of plankton. Plankton support
larger organisms, such as fish and seabirds.
• Upwelling is shown on the next slide.
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