Currents

Compare rivers and surface currents.

Both rivers and surface currents are long, moving bodies of water. However, rivers flow because of the pull of gravity, while surface currents are driven by the wind and by the rotation of the Earth.

The Gulf Stream Current is deflected by North America, causing the current to change direction. What is this concept called?

Continental deflection

What are three factors that control deep currents?

Density, salinity, and temperature; accept also the Coriolis effect.

What three factors control surface currents?

Global winds, the Coriolis effect, continental deflections

What happens to an ocean current when it hits a continent?

It changes direction.

Give two characteristics and one example of each type of current.

Surface currents occur at the surface of the ocean and are caused by global winds; the Gulf Stream is an example. Deep currents occur deep in the ocean and are influenced by water density, salinity, and temperature. The Antarctic Bottom Water is an example.

Do winds and currents flow faster at the equator than at the poles, or more slowly? Think about what you know regarding the shape and rotation of the Earth, the directions of currents, and convection. Make inferences from what you know. Then give reasons to support your answer.

Winds and currents flow faster at the equator than at the poles. One reason equatorial currents are faster is that they are warmer. Another reason is that the speed of the Earth's rotation is much faster at the equator. (A point near the poles and a point at the equator both rotate in 24 hours, but the point at the equator has traveled a much greater distance in that time.)

A stream-like movement of ocean water far below the ocean surface is a

deep current.

Although they flow near the bottom of the ocean, ____________________ sometimes flow on top of other currents.

deep currents

Ocean currents flow from east to west near the

equator

The density of ocean water increases when it

gets colder.

What force makes cold water sink toward the ocean floor?

gravity

How does the Coriolis effect make ocean currents appear to move?

in a curved path

Do global winds directly cause deep currents?

no

The Gulf Stream is an example of a(n) ____________ current.

surface

Which currents carry warm water away from the equator?

surface currents

deep currents

surface currents

What causes ocean water to become denser?

the salinity of water and low temperatures

Can ocean currents be caused by differences in salinity?

yes

Can ocean currents be caused by differences in water temperature?

yes