earth as a system ch. 1 what is the earth system, and where do we humans fit in?

Earth as a SystemCh. 1

What is the Earth system,and where do we humans fit in?

A New View of Earth• What do earth

scientists study?– solid earth, oceans,

oceans, space• In past studied

separate parts– How has this

changed? Why?» now often studied

as a system• b/c realized

parts are connected and interact

A New View of Earth• What sparked this

new view of Earth as system?– space exploration

• “blue marble” photo (Apollo 17)

– satellite imaging– environmental

incidents– deep sea

exploration– computers &

Geographic Information Systems (GIS)

Models & Systems• What is a model?– a simplified representation of an object, process, or

phenomenon– a way to predict if-then scenarios (for the past & future)

• What happens when scientists learn more about the world?– Models can be modified or replaced with a new model

• What is a system?– group of objects or phenomena that

share matter & energy• Ex. Earth’s spheres

– A type of model

Open & Closed Systems• What is an open system?– a system & its surroundings that exchange energy & matter

• How is a closed system different from an open system?– energy can be exchanged… matter CAN’T be exchanged

• Is Earth an open system or a closed system? Why?– technically, open, but usually considered closed b/c exchange

of matter is extremely small

Earth’s Spheres

Examples of how the spheres interact & changes that result…

Overall, Earth is in balance…• Changes to one sphere can have impacts on one or

more or the others– human activities have major impacts on the spheres

• However, overall, Earth is in balance. How?– biogeochemical cycles• carbon cycle• water cycle• rock cycle• … and more

Carbon & Oxygen Cycles

The Water Cycle

EXHALATION

Nitrogen Cycle

Sulfur Cycle

Phosphorous Cycle

SedimentsErosion

Weathering

Deposition

Igneous rock Granite, pumice, basalt

Sedimentary rock sandstone, limestone

Heat, pressure

Cooling & solidification

Heat, pressure (metamorphism)

Magma(molten rock)

Melting

Metamorphic rock slate, marble, gneiss, quartzite

Rock Cycle

The Energy Budget• “energy budget” is

sometimes called “energy cycle” or “energy balance”– amount of energy

that enters should equal amount that exits• What happens if

more energy enters?– heating

• What happens if more energy enters?– cooling

The Energy Budget & the Laws of Thermodynamics

• Can energy be created or destroyed?– No, it can only be transferred & transformed (1st Law)

• Can energy ever be recycled completely?– No, when energy changes it is degraded into a less useful

form & “lost” (in terms of its original form) (2nd law)• “Lost” energy is usually given off as…?

– heat

Chemicalenergy(food)

Solarenergy

WasteHeat

WasteHeat

WasteHeat

WasteHeat

Mechanicalenergy

(moving,thinking,

living)

Chemical energy

(photosynthesis)

Earth’s Surface & the Energy Cycle• How can Earth’s

surface affect the energy budget?– “albedo” is the ability

of a surface to reflect light• What type of surfaces

would have a low “albedo”?– dark & dull

• What type of surfaces would have a high “albedo”?– light & shiny

– changes in surface type change the energy budget

Factors Affecting Rates of Temperature Change Visualization