Earth as a System Ch. 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

Sediments Erosion 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 (1 st 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) (2 nd law) “Lost” energy is usually given off as…? – heat Chemical energy (food) Solar energy Waste Heat Waste Heat Waste Heat Waste Heat Mechanical energy (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