Introduction: Scientific Method

7/18/2019 Introduction: Scientific Method

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What is Geology?

• The study of the Earth – Composition

– Behavior

– History• Geology is often called geoscience or Earth

science

– Relies heavily on…

• Biology

• Chemistry

• Physics

• Mathematics



Subdisciplines of Geology• Engineering Geology/Geological Engineering

– Stability of materials for building things• Paleontology – Ancient life (fossils)

• Stratigraphy/Sedimentology – Layers of rocks and their sequences/sediments and their deposition

• Petrology

– Rocks!• Structural Geology

– Deformed/Damaged Rocks, often related to tectonic plates

• Hydrogeology – Groundwater & surface water

• Volcanology – Volcanoes, active and ancient

• Climatology – Past, present, and future climate interactions

• Geophysics – The physics of the Earth system

• …and the list goes on and on…



GEOLOGY – the science of the Earth, an

organized body on which we live

Main thrust of geology: To understand the changes that take place in and on earth,

and the reasons for those changes. Geology helps us unlock the mysteries of our

environment. The earth, at work for billions of years, has distributed material into

localized concentrations that humans can mine or extract. By learning how the earthworks and how different kinds of substances are distributed and why, we can

intelligently search for metals, sources of energy (e.g.,

coal and petroleum) and gems

A clear understanding of the earth processes

Allow geologists to be among the leadingcaretakers of the environment. Conversely,

geologists have a direct role in ensuring people’s safety and

well being and safety from natural processes

(e.g., earthquakes, volcanic eruption, tsunami).

http://upload.wikimedia.org/wikipedia/commons/9/97/The_Earth_seen_from_Apollo_17.jpg



“The present is the key to the past.”

Principle of Uniformitarianism(the birth of modern geology)

James Hutton (1726-1797) – Scottish medical man, farmer, geologist,

the “father of modern geology)

“In ear ly Chr istendom , geolo gic events were placed with in a

bib i l ica l chrono logy, and catast rophic h appenings were blamed for

features of the land scape. When ro cks s everal thou sand m eters abov e sea

level seemed to have been form ed of sedim ent depos ited in deep waters,

the explanat ion was that wor ldwide inun dat ion had s imply drow ned al l the

earth’s mountains in a matter of days”

Hutton realized that geologic features could be explained through present day-

processes. The time required for these processes to take place had to be

incredibly long . He upset conventional thinking (the world was believed to be

less than 6,000 years old) by writing in 1788, “We find no sign of a beginning

no prospect of an end”.



Principle of Uniformitarianism(the birth of modern geology)

Hutton’s ideas were relatively unnoticed until, Charles Lyell, in his

Principles of Geology book referred to his idea which he referred to as THE

PRINCIPLE OF UNIFORMITARIANISM

The physical processes operating today to modify the earth’s

surface also operated in the geologic past—which is another way of saying

that the laws of nature are unchanging. More succinctly, the principle states

that “THE PRESENT IS THE KEY TO THE PAST”.

UNIFORMITARIANISM vs. ACTUALISM



Geologic Time - Eons

Hadean – “Beneath the Earth”

All Rocks Still Molten

Think “Hot As Hades”

Archean – “Ancient”

Oldest Rocks

Proterozoic – “Former Life”

Simple Organisms

Phanerozoic – “Visible Life”

P r e c

a m b r i a n



Phanerozoic Era

Mesozoic – “Middle Life”

Dinosaurs!

Cenozoic – “New Life”

Now!

Ka = Thousand years ago

Ma = Million years ago

Ga = Billion years ago

1,000 Ka = 1 Ma1,000 Ma = 1 Ga

1,000,000 Ka = 1 Ga

3.75 Ga = ? Ka

Paleozoic – “Ancient Life”



4560 MaEarth andplanetsform

4510 MaMoonforms

4470 MaOldestlunarrocks

4000 MaOldestcontinentalrocks

3800 MaEvidence of erosionby water

2700 MaStart of rise ofatmospheric oxygen

3500 MaRecord of magnetic fieldFossils of primitive bacteria

2500 Ma

Major phaseof continentformationcompleted

542 MaEvolutionary

“Big Bang”

443 MaMassextinction

420 MaEarliest

land animals

125 MaEarliestfloweringplants

5 MaFirst hominids

0.2 MaFirst appearanceof our species,

Homo sapiens

Mass extinctions

359 Ma 251 Ma 200 Ma 65 Ma Present

1500

1000

2000

3000

4000

500

A Brief Journey Through Geologic Time…



The most recent layer is about250 million years old.

The rocks at the bottom of the GrandCanyon are 1.7

– 2.0 billion years old.

The explosive impact of a meteorite createdthis 1.2-km-wide crater in just a few seconds.

Geology Covers an Enormous Range of Scales



Global-scale model of oceantemperatures

Scanning electron microscope image ofa minerals (chrysotile) within dust.

Geology Covers an Enormous Range of Scales



Themes of Course:

• The Earth is a unique, evolving system

• Plate Tectonics is a unifying theory that is essential toexplain Earth processes

• The Earth is very old (~4.6 billion yrs.)

– Geologic time… • Internal and external forces interact at the Earth’s

surface

Internal – volcanoes, earthquakes

External – wind, glaciers

• Geologic phenomena affect our daily environment

Groundwater, Landslides, Oil Reserves, Hurricanes, Weather

Patterns etc.



More Themes:

• Physical aspects of the Earth are linked to life processes

Soils, temperature, water flow, etc…

• The study of geology can increase science literacy

Make better decisions about your environment

• Science comes from observation

People make science happen

Science is based on T he Scienti f ic Method … • Science IS NOT in the business of proving things

• Science is all about gathering data and testing ideas



The Scientific Method

• Science is not subjective

• Results are statements based

on observations

• Results must be reproducible and thoroughly tested

• Scientific discovery is the

results of human efforts…

people just like you!

• Science proves nothing, but

does test ideas!



The Basic Steps of the Scientific Method

• 1- Identifying the problem or questionWhat are we trying to figure out?

• 2- Collecting dataCollect data that addresses the problem

• 3- Propose hypothesisAn idea that is consistent with your collected data

• 4- Test hypothesisIf your idea is correct, then other things should be true too. Test ‘em!Get ‘er done!

Over time, others will test your hypothesis – Does the hypothesis agree with other data?

– Does the hypothesis predict behaviors?• If yes, then the hypothesis may become a theory

• If no, then the hypothesis must be modified or rejected



Hypotheses, Theories, and Laws, Oh My!

• Hypothesis

consistent with your dataother researchers test it

• Theoryconsistent with al l verified data

may be modified if new data is presented

• Scientific ModelCombines many theories and hypotheses

to explain a complex system

• Law

considered absolutely correct throughout

the natural universe (e.g. gravity)

The Moral…

Its not easy to become a theory.



Scientific Method Modern Example:

Upheaval Dome, UT

• Step 1 – Identify the problem/question

– What formed this bizarre geologic structure?



• Circular shape

• Dome structure• Lots of Faults

Collect Data



• Meteor Impact!

– Consistent with

dome structure

and lots of faults

Make A Hypothesis



Hypothesis Testing

• After you submit your findings, someone else reviews

your work and points out that

• Salt deposits can also make circular domes!!• Uh Oh!



Solved!

• In 2008, Researchers from

the University of Vienna:

– Found Shocked Quartz

– Demonstrated that the impact

hypothesis was the only idea

that was consistent with all of

the data

– Now if the communityverifies and reproduces these

results…

• we will have a theory to explain

upheaval dome!



Science?…or Something Else?

• A friend tells you that he read that sandstone is

made of tiny diamonds.

– So small that they are not detectable by any means.

• Is this science? Is it correct?

• String Theory…

– Is it science or philosophy?



The Moral of the Story

• Most hypotheses don’t become theories

• It takes a LOT of data for a hypothesis tobecome a theory

• Ideas that are not testable are not science

G l i Ti



Geologic Time

Hadean: 4600 Ma – 3800 Ma

Proterozoic: 2500 Ma – 542 Ma

Paleozoic: 542 Ma – 248 Ma

Formation of Earth: 4600 Ma

Archean: 3800 Ma – 2500 Ma

Mesozoic: 248 Ma – 65 MaCenozoic: 65 Ma – Now

Introduction: Scientific Method

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