Lecture 2-Earth Science Systems Flashcards
What are the systems and cycles in Earth science?
- hydrologic cycle
- energy cycle
- tectonic cycle
- biogeochemical cycle
- rock cycle
Why is it important to study the Earth?
- Resources obtained from the Earth (I.e., fuel)
- Materials returned to the Earth (solid, liquid, gas wastes)
- Direct impact of Earth processes on humans (e.g. floods)
- impact of humans on Earth processes (e.g. change in atmosphere)
Scientific method
- make an observation(investigate/experiment)
- form a hypothesis to explain observations
- test hypothesis
- multiple tests of hypothesis to support it
- hypothesis becomes a theory
- theory becomes a principle or law
The principle of uniformitarianism
- James Hutton 1795-Theory of the Earth
- ancient features of the Earth are best interpreted in terms of processes that operate at present day
- present is key to the past
What do we now realize is wrong with Hutton’s uniformitarianism principle?
We now recognize there have been big changes in Earth’s process including:
- Long term changes (e.g. evolution of the atmospheres)
- Short term changes (e.g. catastrophic meteorite impacts)
Principle of actualism
A more moderate version of Hutton’s principle
-ancient features of the Earth are to be interpreted in terms of chemical and physical processes thatf operate at present day (accepts exceptations)
Law
Theories which are very well established and which no exceptions are known
Law of conservation of energy
At constant mass the energy involved in physical or chemical change is neither created nor destroyed-it is merely converted from one form to another
What is a system?
A system is a portion of the universe that can be separated from the rest for the purposes of observing changes
Types of systems?
- Isolated system
- Closed system
- Open system
Isolated system
No energy or matter lost or gained (hypothetical)
Closed system
Matter is not lost or gained but energy is exchanged with the surroundings (Earth)
Open system
Both matter and energy is exchanged with surroundings (humans)
Earth is a closed system because..
The small amounts of gas lost or o space and the small amounts of matter gained by meteorites are small compared to mass of the Earth
Major open systems of Earth?
- geosphere
- atmosphere
- hydrosphere
- biosphere
The geosphere
- solid sphere with crust, liquid outer core and solid inner core
- extract oils/minerals from here
- solid inner core contains nickel and iron
- outer core is pliable (plates can move over surface of earth)
The hydrosphere
- oceans
- ice
- rivers and lakes
- groundwater
Is water in atmosphere apart of the hydrosphere
No
The atmosphere
Blanket of gases responsible for:
- composition and structure
- weather systems
- violent weather
- global climate change
The biosphere
- origin and history of life
- biogeography
- fossils
- chemical cycling and life
What allowed for advances in ESS
New scientific tools:
- on the grandest scales through space based instruments on satellites and remote sensing
- on the tiniest scales through advances in techniques such as electron microscopy
And increases in computational power, storage and software (e.g. Graphic information systems GSI) that allow us to store and manipulate massive amounts of observational data
What do we use to study systems
Models
What is a model
An approximation or simulation of a real world system that omits all but the most essential variables of the system
Detail and content of the model depend on the types of questions being asked
Three types of models
- Physical models
- Pictorial or graphical model
- Box model (showing different reservoirs)
