The Science ofThe Science of PHYSICAL GEOLOGY PHYSICAL GEOLOGY

““If your mind is empty, it is always ready for anything; it If your mind is empty, it is always ready for anything; it is open to everything.”is open to everything.” Zen Proverb Zen Proverb

The Science of GeologyThe Science of Geology• Geology is the science that pursues

an understanding of planet Earth • Physical Geology – Examines the

materials composing Earth and seeks to understand the many processes that operate beneath and upon its surface.

• Historical Geology – Seeks an understanding of the origin of Earth and its development through time.

Why Study Geology?Why Study Geology?• Humans and the

natural environment are interrelated. – Natural Hazards – Resources – Energy,

Water, Agriculture, etc.– Environmental Issues

• Understanding past geologic events will help us predict future geologic events.

Humans ask questions to Humans ask questions to understand the natural environmentunderstand the natural environment

• How did the Universe and our Solar System form?• How did the Earth form? How do rocks form?• What is Plate Tectonics?• Why do earthquakes and volcanic eruptions occur? • What governs the location of mountain ranges?• Where do we get energy resources from?• How are gemstones formed?• Where do we get drinking water from?• What factors provide for the best agricultural areas?• What caused the ice ages? What causes global

warming?

Curiosity Leads to Exploration

The Answers are Written in The Answers are Written in the Rocksthe Rocks

Rocks and Fossils are important tools for geologists that tell a story of what Earth

like in the past.

• Life Forms (flora and fauna)

• Plate Tectonics

• Mountain Building

• Volcanic Eruptions

• Age Dating

• Paleoclimate

• Extinctions

• Global Sea Level Rise and Fall

• Ice Ages

How do geologists read the story recorded in the rock and fossil record?

Science operates through the Science operates through the use of the use of the Scientific MethodScientific Method

““A poverty of ideas is a more serious deficiency than A poverty of ideas is a more serious deficiency than faulty reasoning”faulty reasoning” Robert MagnanRobert Magnan

• Observe• Raise Question• Form Hypothesis • Test Hypothesis• Gather Data• Modify Hypothesis• Retest Hypothesis

Limits of ScienceLimits of Science

• Questions (hypotheses) must be testable. • Results must be repeatable.• No moral or aesthetic judgments.• Can only test the natural, physical world.

Scientific discoveries may be controversial… especially when they are first made.

What is a Hypothesis? What is a Hypothesis? What is a Theory?What is a Theory?

What is a Hypothesis?What is a Hypothesis?

• Hypothesis – A tentative (or untested) explanation.

• A hypothesis that survives repeated testing and challenges, and is supported by a large body of evidence, may be elevated to the status of a Theory.

What is a Theory?What is a Theory?

• Theory – A well-tested and widely-accepted explanation of natural phenomenon that the scientific community agrees best explains certain observable facts.

Examples of Theories:Theory of Relativity

Plate Tectonics Theory Evolutionary Theory

Atomic TheoryCell Theory

What is a Theory?What is a Theory?• It is important to understand that the term “theory” has very

different meanings to scientists and to the general public.

• To a scientist,– A theory is not just a wild idea, a guess, or a belief. – It is based on objective facts.– Theories have survived close examination, and can be accepted

with confidence.– A theory represents knowledge that has very high probability of

being correct. – A theory remains open to tests and revision….that can make

theories stronger/weaker.

• Whereas, in common language, – “Theory” implies a lack of knowledge or a guess, conjecture,

opinion, speculation. In this usage, a theory is not necessarily based on facts.

What is Scientific Law?What is Scientific Law?

• Paradigm – A theory may become a paradigm (a predominant worldview in the realm of human thought) or

• Scientific Law after further testing and acceptance.

• Example: Law of Gravity

Peer-Reviewed Journals – Peer-Reviewed Journals – Primary LiteraturePrimary Literature

Science Science MagazinesMagazines

Secondary LiteratureSecondary Literature

Summary of Scientific MethodSummary of Scientific Method

1. Make observations:• The shape of Earth’s continents appear to fit

together like pieces of a jigsaw puzzle.

2. Identify a question or problem:• At some time in the past, were the continents

joined together forming one large land mass?

3. Develop working hypothesis (idea to explain the observations):• During Earth's history, the continents were joined

together into one giant supercontinent (called Pangaea meaning "All Lands" in Greek).

Summary of Scientific MethodSummary of Scientific Method4. Determine ways to test the hypothesis by

experimenting and either accept, reject, or modify the hypothesis:

• Develop tests that support or disprove that the continents were once joined.

• Develop tests that support or disprove that the continents have moved (and may still be in motion).

• The simplest explanation is typically the best.• What is some of the information we can use to do this?

• Fit of Continents• Rock Types• Rock Structures• Fossils• Paleoclimate Data • Apparent Wandering of the Earth's Polar Regions• Geodetic evidence that continents are moving at a

measurable rate

Summary of Scientific MethodSummary of Scientific Method5. Collect Data6. Analyze Data:

• Try to piece continents back together based on data collected

7. Interpret Data:• Are there trends or correlations?

8. Support or refute hypothesis and develop new hypothesis, if appropriate.

9. Repeat Steps 4 thru 10.10. Only after repeated testing of the hypothesis, in

which it gains considerable experimental or observational support, is it accepted and a theory is established.

11. A theory ultimately may become a paradigm or scientific law.