Introduction to Earth ScienceEarth Science

Chapter 1

Mr. Willis Earth and Space Science WH

Encompasses all sciences that seek to understand Earth Earth’s neighbors in space

Earth Science includes Geology – literally the “study of Earth” Physical Materials composing the Earth Historical study of the origin and development of

the Earth Oceanography – a study of the ocean Meteorology – the study of the atmosphere and the

processes that produce weather Astronomy – the study of the universe

Earth Science

Environment Surrounds and influences organisms Physical environment encompasses water,

air, soil, and rock Term “environmental” is usually reserved for

those aspects that focus on the relationships between people and the natural environment

People and the environment

Population Population of the planet is growing rapidly Rate of mineral and energy usage has climbed

more rapidly than the overall growth of population

Current populations US 314,340,477 (US Census Bureau) World 7,038,328,935 (US Census Bureau) World Leader:

China

People and the environment

Figure 1.3 in text

Figure 1.2 in text

Resources An important focus of the Earth sciences Includes water, soil, minerals, and energy Two broad categories

Renewable – can be replenished (examples include plants and energy from water and wind)

Nonrenewable – metals (examples include metals and fuels)

People and the environment

Figure 1.6 in text

Figure 1.1B in text

Environmental problems

Local, regional, and global Human-induced and accentuated

Urban air pollution Acid rain Ozone depletion Global warming

* Natural hazards Earthquakes Landslides Floods Hurricanes World population pressures

People and the environment

Science assumes the natural world is Consistent Predictable

Not always the case

Goal of science To discover patterns in nature To use the knowledge to predict

Scientific inquiry

An idea can become a Hypothesis (tentative or untested explanation) Theory (tested and confirmed hypothesis) Paradigm (a theory that explains a large

number of interrelated aspects of the natural world)

Scientific method Gather facts through observation Formulate hypotheses and theories

Scientific inquiry

Scientific knowledge is gained through Following systematic steps

Collecting facts Developing a hypothesis Conduct experiments Re-examine the hypothesis and accept, modify,

or reject Theories that withstand examination Totally unexpected occurrences

Scientific inquiry

In Earth and Space Science observations are made from smallest objects (atoms) to the largest (stars) Types of scale within Earth and Space Science Mohs Scale of Hardness

Minerals Hardness Richter Scale

Earthquakes Geologic Time Scale

Age of Earth Fujita Scale

Tornados HR Diagram

Stars

Scaling in Earth Science

Figure 1.6 in text

Figure 1.7 in text

Humans and the Environment Paper

Is the recent increase in human fatalities/property damage globally from natural disasters (i.e. hurricanes, floods, tornados, etc.) a function of the global warming/climate change or human population growth/encroachment on areas where man was not intended to habitate.-Using at least four sources, develop a thesis that clearly states your position on the issue and write a 4-5pgs persuasive paper on this topic.-Be sure to include the concepts of the Earth System in your discussion.

Origin of Earth Most researchers believe that Earth and the

other planets formed at essentially the same time

Nebular hypothesis Solar system evolved from an enormous rotating

cloud called the solar nebula Nebula was composed mostly of hydrogen and

helium

Early evolution of Earth

Origin of Earth Nebular hypothesis continued

About 5 billion years ago the nebula began to contract

Assumes a flat, disk shape with the protosun (pre-Sun) at the center

Inner planets begin to form from metallic and rocky clumps

Larger outer planets began forming from fragments with a high percentage of ices

Early evolution of Earth

The Nebular hypothesis

Figure 1.8 in text

Formation of Earth’s layered structure As Earth formed, the decay of radioactive elements

and heat from high-velocity impacts caused the temperature to increase Iron and nickel began to melt and sink toward the center Lighter rocky components floated outward, toward the

surface Gaseous material escaped from Earth’s interior to

produce the primitive atmosphere

Early evolution of Earth

Hydrosphere Ocean – the most prominent feature of the

hydrosphere Nearly 71 percent of Earth’s surface About 97 percent of Earth’s water

Also includes fresh water found in streams, lakes, and glaciers, as well as that found underground

Earth’s “Spheres”

Atmosphere Thin, tenuous blanket of air One half lies below 5.6 kilometers

(3.5 miles) Accounts for all gases in and around the Earth.

Biosphere Includes all life Concentrated near the surface in a zone that extends

from the ocean floor upward for several kilometers into the atmosphere

Earth’s “Spheres”

Solid Earth Based on compositional differences, it consists of

the Crust – solid material at the surface Mantle- 82% of the earth’s volume Core – Inner (radius ~1216km/754mi) Outer

(2260km/1400mi) Divisions of the outer portion are based on how

materials behave Lithosphere – rigid outer layer (avg. 100km in

thickness) Asthenosphere – weak sphere Divisions of Earth’s surface – continents and ocean

basins

Earth’s “Spheres”

Earth’s layered structure

Figure1.14 in text

A closer look at the geosphere

Figure 1.16 in text

Earth is a dynamic body with many separate but highly interacting parts or spheres

Earth system science studies Earth as a system composed of numerous parts, or subsystems On a macro-scale

Hydrosphere, geosphere, biosphere, and atmosphere

System – any size group of interacting parts that form a complex whole

Earth system science

System Closed systems are self-contained

(e.g., an automobile cooling system) Open systems – both energy and matter flow

into and out of the system (e.g., a river system)

Earth system science

Feedback mechanisms Negative-feedback mechanisms resist change

and stabilize the system Positive-feedback mechanisms enhance the

system Earth as a system

Consists of a nearly endless array of subsystems (e.g., hydrologic cycle, rock cycle)

Earth system science

Earth as a system Sources of energy

Sun – drives external processes such as weather, ocean circulation and erosional processes

Earth’s interior – drives internal processes including volcanoes, earthquakes and mountain building

Humans are part of the Earth system As the dominant species on the planet, our

geologic-footprint is also the greatest.

Earth system science

End of Chapter 1