Intro to Earth ScienceCh. 1

200

Three Scientists, Three Individuals• Carl Sagan– astronomer– author• Pulitzer Prize winner

• Enriqueta Barrera– geologist– paleontologist

• Evan B. Forde– oceanographer• NOAA Researcher

Different Lives, Common Goals• What do you think of when you think of a scientist?– Scientists are very different in many aspects

(background, where they work, what they study, etc.).• Do scientists have anything in common?– Yes, the “scientist’s mind”• way of looking at the world with both logic & sense of wonder

Qualities of Scientific Thinking• What are the qualities of scientific thinking?– curious– observant– use evidence• material or data that can be measured to verify or test a

prediction

– creative/inventive/innovative• form hypothesis-tentative explanation for an observation

– skeptical/questioning– logical

• What is science?– an organized process that produces a body of knowledge

about nature• based on observation of phenomenon or their effects &

experimentation in order to attempt to explain the cause of those effects• goal is to produce useful models of reality

– Can you prove anything in science?• No… there is constant refinement as new information becomes

available or information is looked at differently.

• What is technology?– application of scientific knowledge for practical purposes

What is Scientific Inquiry? Sec. 1.5

• law (describes “what”)– statement of great generality of something in nature

which seems to always be true• does not give an explanation of “mechanism” or “why”

something happens

• examples– Nicolas Steno’s Law of Superposition– Newton’s Law of Universal Gravitation

What is a Law?

• theory (explains “why”)– most logical & complete explanation of event that

happens in nature (under certain conditions)• can be used to predict what will happen as long as those

conditions are met

– based on evidence tested & supported many times (similar to hypothesis but has withstood the test of time)• can change/be refuted based on new evidence

– often explains law– has a broad range of significance & application

• NOT a “hunch”, “opinion”, or “guess” as often used in common language!!!

What is a theory? video clip What is a Theory?

What is a theory? video clip

– Theory of Plate Tectonics

–Big Bang Theory

Examples of Theories

• hypothesis (is a tentative explanation)– developed to:• investigate a scientific question & MUST be testable• explain observations (such as patterns in nature or connections

between two variables)• predict the outcome of an experiment (based on observations

or prior scientific knowledge)• guide investigator in seeking & paying attention to right data

– is NOT proved true or correct (or false or incorrect)• is supported (or refuted) by the data

– is NOT written as a question…• may use “If _(IV)_, then _(DV)_, because __.” format

– If an object is a darker color, then it will heat faster, because dark colors have lower albedo (reflectivity) than light colors.

What is a Hypothesis?

The Scientific Method

http://www.sciencebuddies.org/science-fair-projects/overview_scientific_method2.gif

Pose a problem/Ask a question

Do not necessarily have to go in order.

The Scientific MethodA. identify

problem/question to investigate– gather background

information

B. form hypothesis– “If _(IV)_, then

_(DV)_, because __.”

The Scientific MethodC. test hypothesis–using a controlled

experiment• experimental design

(procedure)–written so that others

can easily follow it» like a recipe

(detailed, logical sequence, amounts included, diagrams of set-up, etc.)

• to be valid has to have two parts…

What is a controlled experiment?1. tests one variable & all others are kept the same– independent variable (IV)

» factor being tested/changed by scientist (to see if it has an effect on the DV)• What “I” change

–dependent variable (DV)» factor being measured (to see if it changes in response to a

change in the IV)

– constants or (controlled variables) (C/v)» all other factors that are not being tested & must be kept the

same (so can’t affect the results)

What is a controlled experiment?2. two groups must be tested

a) control group» nothing is being tested

▪IV is absent

» “standard” which experimental group is compared to ▪to see if IV had an effect

b) experimental group» “test” group(s) ▪IV is changed (one or more variations)

» “test” group compared to “standard” control group ▪to see if IV had an effect

• also should have multiple trials (replicates)–ensure results are accurate

D. make observations & collect data (quantitative &/or qualitative)

– organize in data tables

E. interpret data & analyze results– graphs

F. draw conclusions– support/reject hypothesis (NOT prove/disprove)• conduct additional experiments (revise or discard

hypothesis if rejected)

G. communicate results– report & publish

The Scientific Method

How does the % silica (sand) content of “lava” (liquid soap) affect its rate of flow (cm/sec)?

• independent variable– % silica content of the lava

• dependent variable– rate of flow (cm/sec)

• constants (controlled variables)– overall volume of mixture poured, type of soap, type of sand, angle of

ramp, temperature of mixture, width of ramp, length of ramp……………

• experimental group(s)– groups w/ different % of silica (5%, 10%, 15%, 20%, 25%)

• control group– group w/o silica (0%)

What is the Earth

system, & where do we

humans fit in?

What do you see?

What does it make you wonder?

What do you think about

that?

What is Earth Science? Sec. 1.1

• the group of sciences that deals with Earth & its neighbors in space

• What are the 4 main branches of Earth Science?– geology• Earth properties, processes, & history

– meteorology• atmospheric properties & processes• weather & climate

– astronomy• solar system & universe properties, processes, & history

– oceanography• ocean, coastal, & seafloor properties & processes• marine life

What is Earth Science?• Understanding Earth is not easy… Why?– Earth is a dynamic planet w/ a long & complex history.• Earth is always changing!!!

A View of Earth: Earth’s Major Spheres sec. 1.2

• Earth was traditionally divided into 4 major spheres:– hydrosphere

• water– atmosphere

• air– geosphere

• rock– biosphere

• life

• Now, 5th sphere is often added…– anthrosphere

(anthroposphere)• human

Earth System Science sec. 1.4

• In past studied Earth as separate parts–How has this changed? Why?• now often studied as a system b/c realized parts are

connected and interact

Earth’s Major SpheresAct as a System

Examples of how the spheres interact & changes that result…

Earth as a System• 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)

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… but 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

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

more of 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”– sometimes called

“energy cycle” or “energy balance”• energy in should

= energy out–What happens if

more energy enters?» heating

–What happens if more energy leaves?» cooling