Visualizing Earth Science By Z. Merali and B. F. Skinner Chapter 1 – Introduction to Earth Science

Chapter Overview Earth Science The Earth in Space Humans and Earth

Science and the Scientific Method Systematic approach to studying natural processes Make observations Formulate a hypothesis Conduct tests of the hypothesis Evaluate and generalize Earth Science The scientific study of aspects of Earth

Science and the Scientific Method

Systems The Systems approach Deconstruct Universe into interconnected elements or units Identify processes connecting and boundaries separating systems

Types of Systems Systems classified according to boundary interactions with the environment Isolated: No energy or matter is exchanged Closed: energy is exchanged but not matter. Open: energy and matter can be exchanged with environment

The Earth System A(n almost) closed system Earth System Science Treat Earth Science as a single field of study Emphasis on studying interconnections between Earth subsystems

Principal subsystems of the Earth System Four principal open subsystems or “spheres” The lithosphere The hydrosphere The atmosphere The biosphere Each interacts with the others Most intensely in the life zone

Feedback Mechanisms How feedback works System interacts with environment Interaction produces change in the system System responds to the change System response “feeds back” or affects the change in the system Feedback Mechanisms System – Environment interaction cycles that change open systems Positive feedback Enhance change in systems Negative feedback Reduce change in systems

The Earth in Space The Solar System The Earth – Our planet One of eight large, spherical bodies orbiting the Sun Third from the sun A relatively smaller, denser body The inner planets: Mercury, Venus , Earth and Mars are the terrestrial planets Larger, less dense planets: Jupiter, Saturn, Uranus and Neptune are jovian planets The Earth is uniquely suitable for sustaining life

The Earth in Space The Solar System

The Earth in Space The Terrestrial Planets General characteristics of terrestrial planets Similar densities – a little greater than common rocks Dense metallic core surrounded by less dense rocky layer A result of partial melting of planets in their early history Thin atmospheres Warmer temperatures

The Layers of the Earth Layers by composition A dense two-layer metallic core A solid inner core A liquid outer core – responsible for the Earth’s magnetic field Composed of iron and nickel A less dense rocky middle layer – the mantle A thin brittle rocky outer layer – the crust

The Layers of the Earth Layers by composition

The Layers of the Earth Layers by rock strength Rocky layers (mantle and crust) have distinct structures based on rock strength The lithosphere The crust and upper mantle Strong but brittle cool rock The asthenosphere Easily deformed rock Higher temperature and increased pressure The mesosphere Very high temperature and intense pressure Strong rock

The Layers of the Earth Layers by rock strength

The unique Earth The life supporting planet Presence of Oxygen in the atmosphere Presence of Water Hydrosphere contains solid, liquid and gaseous water The Biosphere (System) Contains all life on Earth Interacts with surroundings and with itself Changes and shapes its own environment Soil – layer of loose debris formed by weathering

The unique Earth The geologically active planet Tectonic activity The lithosphere is broken into large slabs or plates There is large scale movement of plates Plate tectonics continually reshapes the surface of the Earth

The unique Earth

The unique Earth The geologically active planet Lithosphere shaped by tectonics Older lighter plates float higher over the asthenosphere Form the continents Composed mainly of granitic rock Newer dense plates sink deeper into the asthenosphere Form the oceans Composed of basaltic rock

Humans and Earth Population growth Growth in human population demands increasing resources Population growth and its effects on food and resources Debated among policy makers and academia Needs a response to sustain present resource levels

Humans and Earth Resource management Natural resources are often scarce Renewable resources Can be replaced through natural processes The timescale of replacement is shorter than the timescale of use Nonrenewable resources Cannot be replaced within the timescale of use

Resources and Modern Society Humans and Earth Resources and Modern Society Use of resources in the US and the most industrialized economies - Disproportionately large in comparison with the world - Energy resources Used at rate over four times the world average Dependence on external imports to sustain levels of use

Resources and Modern Society Humans and Earth Resources and Modern Society

Motivation for the study of Earth Science Understanding the Earth system Provides an appreciation of the Earth System as a closed system All material resources are limited Sustaining resources requires understanding processes and understanding time-scales Provides an understanding of Geological features Phenomena and Natural hazards

Motivation for the study of Earth Science What ?

Chapter Summary Earth Science and Earth Scientists Use the scientific method Study the Earth as a closed System Study Earth System mechanisms and processes Earth’s place in the Universe Earth is a planetary body in the solar system Earth is unique in many aspects It sustains life It is geologically active Human interaction with the Earth Earth’s resources are limited Resources management must be understood and applied