Standard 5.b -- Students know the relationship between the rotation of Earth and the circular motions of ocean currents and air

in pressure centers.

Why We Should Care:

• It helps to explain how the weather moves across the sky

• It explains why we have the climate that we do here in California

What is a fluid?

A fluid is a substance that conforms to the container that it is in.

Is water a fluid?

Is a brick a fluid?

Is air a fluid?

Fluids (liquids and gases) are easily influenced by other things.

Air moves out of the way when you walk through it

Air and water both behave in similar ways because they are fluids.

Water flows down the slightest hill because of gravity

What fluids are present on or above the surface of the Earth?

• The ocean (water)

• The atmosphere (air)

They are easily influenced by other forces

Heat from the sun warms air enough that it rises…but it is not the same amount at every place on the globe.

As you move north or south, the same amount of sun gets spread out over a greater area, so it is not as warm.

1st Factor that Affects Air Currents --

Energy from the Sun

•Warm air at the equator rises until it hits the stratosphere (upper layer of atmosphere)

• It then spreads out and cools.

•Eventually, it cools enough to sink and return to Earth

•This process creates a convection current

This convection current is called a Hadley cell and it looks like this in its simplest form.

But here’s the problem…the Earth is spinning.

2nd Factor that Affects Air Currents –

Spin of the Earth

Each current of air close to the Earth’s surface deflects (turns) because the Earth is spinning.

This is called the Coriolis effect.

This process makes three separate cells in each of the hemispheres.

In Northern Hemisphere, rotation is clockwise (right)

In Southern Hemisphere, rotation is counterclockwise (left)

Wind Type Latitude Direction of Air Current

Trade Winds 0 – 30 degrees blows west

Wind Type Latitude Direction of Air Current

Trade Winds 0 – 30 degrees blows west

Prevailing Westerlies 30 – 60 degrees blows east

Wind Type Latitude Direction of Air Current

Trade Winds 0 – 30 degrees blows west

Prevailing Westerlies 30 – 60 degrees blows east

Polar Easterlies 60 – 90 degrees blows west

Surface Currents

• Surface currents are movements of water that flow in a horizontal direction on the ocean’s surface.

• The surface currents develop from friction between the ocean and the wind that blows across the surface.

air flow

• Below are the surface currents throughout the worlds’ oceans.• The direction of the surface currents correspond to the winds that

blow above the water

westerlies

westerlies

trades

Gyres

• Numerous surface currents work together to form large circular patterns called gyres.

• The gyres rotate in opposite directions because of the different air current zones that drive the surface currents

These surface currents are ultimately responsible for distributing heat around the globe.

They move warm water from the equator toward the poles.

Why We Should Care:

•These currents regulate the world temperatures…if they shut down, we could be thrown into another ice age

Standard 5.d -- Students know properties of ocean water, such as temperature and salinity, can be used to explain the layered structure of the oceans, the generation of horizontal and vertical ocean currents, and the geographic distribution of marine organisms.

Density currents are different from surface currents because they move vertically rather than horizontally.

They are driven by differences in density of ocean water.

Density: how much mass a substance has in a certain volume of space

Mass: how heavy the molecules are

Volume: how much space the molecules take up Examples: Water has a density of 1.0 g/cm3 while lead has a density of 11.3 g/cm3.

More dense

more molecules in a specific space, tends to sink

Less dense

less molecules in a specific space, tends to rise

Factors that Affect the Density of Ocean Water

1. Temperature

When water heats up, the molecules move faster and take up more space.

+H H

-O

+

+H H

-O

+

+H H

-O

+

+H H

-O

+

+H H

-O

+

+H H

-O

+ +H H

-O

+

+H H

-O

+

+H H

-O

+

+H H

-O

+

+H H

-O

+

Cold Water:

tightly packed more dense

sinks

Warm Water:

spacious less dense rises

Because the Earth is tilted, the sun’s rays hit the Earth differently, called differential heating. This causes the density of sea water to vary with location.

Water at the poles:least direct sun

coolestmore dense

Water at the Equator:most direct sun

warmestless dense

2. Salinity

When salt gets dissolved in water, more molecules are crammed into the same amount of space

+H H

-O

+

+H H

-O

+

+H H

-O

+

+H H

-O

+

Cl -

Na+ Cl -

Na+

+H H

-O

+ +H H

-O

+

+H H

-O

+

+H H

-O

+

Salt Water:

tightly packed more dense

sinks

Fresh Water:

spacious less dense rises

Sea salt is actually a mixture of many different substances

These substances come from two sources:

1.Weathered rocks – runoff breaks down rock and carries the sediments to the ocean

2.Volcanic gases – eruptions spew gases in the air which eventually land in the ocean

Why is the salinity so low at the Equator?

Lots of rain which dilutes the ocean

Why is the salinity so high at 30° N and S?

Lots of sun (deserts) evaporates ocean water making it salty

Density currents create the Ocean Conveyor Belt. It is a large current system that runs throughout the world.

It consists of:

•Warm surface flow (at the ocean surface)

•Cold subsurface flow (at the ocean floor)

The circulation current sinks in the North Atlantic because of the cold temperature of the high latitudes (high density water)

The current rises in the Indian Ocean because of the excessive rain and in the Pacific Ocean because the water is slightly warmer (low density water)

The warm surface flow gives much of Europe and North America a warm climate because of warm water brought northward.

As the Earth warms, polar ice will melt making the water less dense, slowing down the sinking process and shutting down the entire belt.

Much of the Northern Hemisphere would be thrown into an ice age.

Ice Age if Current shuts down

Name Percent Temp Salinity Density

Surface 2% Warm Low Low

Transition 18% Medium Medium Medium

Deep 80% Cold High High

Ocean Layers

Name Percent Temp Salinity Density

Surface 2% Warm Low Low

Transition 18% Medium Medium Medium

Deep

Name Percent Temp Salinity Density

Surface

Transition

Deep

Name Percent Temp Salinity Density

Surface 2% Warm Low Low

Transition

Deep

Name Nutrients

Organisms

Surface

Transition

Deep

Name Nutrients

Organisms

Surface Poor Phytoplankton (need light) Zooplankton (eat phytoplankton)

Transition Medium Larger marine life

Deep Rich Decomposing organisms

Name Nutrients

Organisms

Surface Poor Phytoplankton (need light) Zooplankton (eat phytoplankton)

Transition

Deep

Name Nutrients

Organisms

Surface Poor Phytoplankton (need light) Zooplankton (eat phytoplankton)

Transition Medium Larger marine life

Deep

Upwelling is a process that brings nutrients from the bottom of the ocean to the surface.

Wind blows water at the surface driving it away. This allows lower layers to move upward bringing nutrients to the surface.

Upwelling

Standard 7.b -- Students know the global carbon cycle: the different physical and chemical forms of carbon in the atmosphere, oceans, biomass, fossil fuels, and the movement of carbon among these reservoirs.

Why We Should Care:

• We are active participants in the cycle

• There is debate about how humans affect the cycle and ultimately the global climate

• Carbon’s flexibility allows it to form many different types of compounds, which allows carbon to travel through the different parts of the environment

Atmosphere: The air above the Earth’s crustRocks: The Earth’s crustFossil Fuels: Substances made of once-living materialsOceans: The water on the Earth’s crustBiomass: All living organisms on the planet

Carbon in Rocks

• Primary Form: – Calcium carbonate

(CaCO3)

• % of world-wide Carbon storage: – 99.9%

• Formed by:– Sedimentation from the

ocean

• Recycled through:– Volcanic eruptions to

make CO2 in the atmosphere

Carbon in the Atmosphere

• Primary Form: – Carbon dioxide (CO2)

• % of world-wide Carbon storage:

– 0.001%

• Made by:– Volcanic eruptions from rock– Diffusion from the ocean– Respiration from biomass (living

things)– Combustion of fossil fuels

• Recycled through:– Precipitation to

make H2CO3 & CO3 in the ocean

– Photosynthesis to make C6H12O6 in biomass

Carbon in the Ocean

• Primary Forms: – Carbonic acid (H2CO3)

• % of world-wide Carbon storage: – 0.08%

• Made by:– Precipitation from the

CO2 in the atmosphere

• Recycled through:– Diffusion to make CO2

in the atmosphere– Sedimentation to make

CaCO3 in rocks

Carbon as Fossil Fuels

• Primary Forms: – Carbon/coal (C) and

methane (CH4)

• % of world-wide Carbon storage: – 0.009%

• Formed by:– Decomposition of

biomass (living things)

• Recycled through:– Combustion to make CO2

in the atmosphere

Carbon in the Biomass

• Primary Form: – Glucose (C6H12O6)

• % of world-wide Carbon storage: – 0.004%

• Formed by:– Photosynthesis of

CO2

• Recycled through:– Respiration to make

CO2 in atmosphere

– Decomposition to make CH4 and C in fossil fuels

Carbon Cycle Processes• Respiration: using O2 gas to break down C6H12O6 and releasing CO2. This is done by animals

• The opposite is called photosynthesis

C6H12O6 + O2

air

CO2

atmosphere

Converts sugar to carbon dioxide

Respiration

Carbon Cycle Processes• Photosynthesis: Plants breathe in CO2 gas and with sunlight make C6H12O6 and releasing O2

• The opposite is called respiration

C6H12O6 + O2

air

CO2

atmosphere

Converts carbon dioxide to sugar

Photosynthesis

Atmosphere

Form = CO2

Ocean

Form = H2CO3, CO3

Rock

Form = CaCO3

Fossil Fuels

Form = CH4, C

Biomass

Form = C6H12O6, C6H10O5

Combustion

Volcanic Eruption

Sedimentation Decompositio

n

Photosynthesis

Precipitation

DiffusionRespiration

There are two sources of energy that drive the carbon cycle….

The sun is an external source of energy. It enters the carbon cycle when plants experience photosynthesis.

Magma from the Earth’s interior is an internal source of energy. It enters the carbon cycle when underground rock melts.

AnimationAnimation

• http://epa.gov/climatechange/kids/movies/carbon_cycle_version2.swf