Upload
others
View
3
Download
0
Embed Size (px)
Citation preview
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.
A
B
C
D
E
F
G
H
I
*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.