Ocean Currents &

Climate

Kyrene Middle School

6th Grade Science

Ocean Water

Most (97%) of the water on Earth is salt

water

Every 100g of ocean water contains an

average of 35g of salt

Salinity: the measure of the amount of

dissolved salt in water

Saltwater Why is it easier to swim in an ocean or sea?

Salt water has a greater density than fresh water.

Density is how heavy something is for its size; the measure of the amount of matter packed into a given space or how close or far apart the molecules of an object are.

A rock is more dense than a sponge of the same size.

Because salt water is denser than fresh water it can "hold up" more weight, making it easier for you to float or swim.

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*The phrase “rivers within an ocean” refer to the ocean’s currents.

The water in the oceans is always moving.Brainpop:

Ocean Currentsanimation

Ocean Currents

Ocean current is a mass of moving water

Called “ a river within the ocean”

2 types of currents

1. Surface currents These waters make up about 10% of all the water in

the ocean.

These waters are the upper 400 meters of the ocean.

2. Deep water currents These waters make up the other 90% of the ocean

These waters move around the ocean basins by density driven forces and gravity.

The density difference is a function of different temperatures and salinity

These deep waters sink into the deep ocean basins at high latitudes where the temperatures are cold enough to cause the density to increase.

Factors that affect Currents

Heat from the sun: warm water rises; cold water sinks

Earth’s rotation: The Earth rotates at 1600 km/h at the equator in an eastward direction.

Currents below the equator flow in a counterclockwise direction. Currents above the equator flow in a clockwise direction

Wind: Circulating winds push surface water in different directions

Continental Land: large land masses cause currents to turn & change direction

Salinity of the water: Salinity is the measure of dissolved solids or chemicals in the water. More salt/density – rises; less dense - sinks

The Gulf Stream

Powerful, warm, North Atlantic current

Travels eastern coast of US towards

Europe

Currents Affect Climate

Ocean currents have a huge impact on our weather.

If not for the ocean currents, the global climate would be similar to an ice age.

Warm currents bring warm air; cold currents bring cold air

Every three to seven years there is a weather phenomenon called El Niño, which is caused by a shift in ocean currents.

animation

The North Atlantic Current is the

clockwise movement of warm waters

that moves along the coast of

northwestern Europe where it has a

considerable warming influence on

the climate.

Some speculate that if global warming

occurs it could melt the polar glaciers

which would send a rush of cold water

into the NAC thus stopping it. Without

the NAC pumping warm, tropical water

to the North Atlantic, average

temperatures would cool in Europe

and North America by 5°F or more in

just a few years. It would cause

enough cooling to bring snows in

June and killing frosts in July and

August to New England and northern

Europe

Day After Tomorrow Clip #1 Day After Tomorrow Clip #2

This movie depicts what could happen if the currents cease to

bring in warm temperature. Although it is very unlikely that this

would happen so suddenly it is still a good wake up call to be

aware of our environment and how we effect it.