Introduction to Earth Science Chapter 1

What is Earth Science Section 1

Earth Science Earth science is a group of sciences that deals with the Earth and its surroundings The main subdivisions of earth science are Geology Oceanography Meteorology Astronomy

Geology Geology literally means “the study of Earth” Divided into two areas - physical geology and historical geology Physical geology is the study of materials that make up Earth and how they shape our planet Historical geology tries to understand the processes that have occurred throughout Earths history

Oceanography Oceanography is the study of the composition and movements of seawater They also study coastal processes, the seafloor, and marine life

Meteorology Meteorology is NOT the study of meteors. Meteorology is the study of the atmosphere and how weather and climate change

Astronomy Astronomy is the study of the universe The observations and findings made by astronomers can help us to understand Earth and its past

How was Earth formed? The nebular hypothesis gives the most commonly accepted explanation of Earths formation It says that there was a large cloud of hydrogen and helium that kept getting bigger. As it got bigger, it developed a center of gravity. Gravity would cause small clusters of gas to gather, creating stars and planets

A View of Earth Section 2

Earth’s Major Spheres In order to better study earth, scientists have divided Earth into a few major spheres, or portions Earth’s major spheres are the hydrosphere, the atmosphere, the geosphere, and the biosphere All four major spheres interact with each other

Hydrosphere Deals with Earths water, including the water cycle 97% of Earths water is located in the oceans. The remaining 3% of water is included in lakes, rivers, groundwater, and glaciers Fresh water is important for sustaining life for many living things on Earth

Atmosphere The atmosphere is the layer of gases that surround earth The atmosphere helps to protect from the sun and from stellar bodies, like meteors It also provides the gases that we breath Earths surface might look similar to the moon, if not for the atmosphere

Geosphere The geosphere is made up of the rocky parts of earth The geosphere is divided into different parts, based on what its made of - the core, the mantle, and the crust The crust is the outer layer and the core is the innermost layer

Biosphere The biosphere is made up of all living things on Earth. You will learn more about the biosphere in biology - assuming you pass this class

Plate Tectonics Earth’s surface is ever- changing. There are two types of forces working on Earth - constructive forces and destructive forces that constantly change how the surface looks Plate tectonics is a theory that explains how these forces change the earth

Representing Earth’s Surface Section 3

Why Map? How Map? Maps are used to help get from one place to another In the old days, maps were made from explorers who charted undiscovered regions Over the years there have been many styles of maps to be created with different purposes

Global Grid In an effort to make cartography (map making) easier and more universal, a global system was adopted The equator is the imaginary line that circles the globe half way between the north and south pole. Latitude is measured in degrees north or south of the equator The prime meridian is an imaginary line drawn from the north pole to the south pole through Greenwich, England. Longitude is measured in degrees east or west of the prime meridian

Lines of latitude and longitude

Types of Maps There are several different types of maps used for different purposes No matter what type of map, some part of the representation will be off - either shape or size. The types of maps aim to minimize this distortion

Mercator Projection - size and distances are distorted, but directions are accurate

Robinson Projection - map that most accurately shows size, distance and direction

Conic Projection - A type of map with little distortion in lines of longitude, but may have large distortion over lines of latitude

Gnomonic Projections - a distance and directions are distorted, but accurately shows the shortest distance between two points

Topographic Maps A topographic is a map used to show changes in elevation Changes in elevation are shown using contour lines. A contour line is a line drawn that connects areas of equal elevation A contour interval shows the difference in elevation between two lines

Topographic Map

1) If black (the first layer of your model) is sea level, what elevation is each of the following points? (the contour interval = 10 ft.) A _______ B C 1 2 3 2) Which is the steepest slope on the hill? (north, south, east, or west?) How do you know? 3) What is the difference in elevation between the second and fourth layers of your model? 4) If you were to build a house on this hill, where is the flattest part of the land form?

Map Scale A scale is used to accurately draw a map so that relative distances remain the same. For example, a map might use 2 inches to show a real distance of one mile Why are maps scaled?

Geologic Map A geologic map is used to show the types and ages of the rocks that are exposed at the surface They are useful when examining the geologic history of an area

Earth System Science Section 4

What is a System? A system is a group of interacting parts that form a more complex whole Earth science is often studied as a system with several groups interacting and affecting each other. For example, the hydrosphere, atmosphere, and geosphere all interact during the water cycle So, in order to understand one system, we often need to understand many other systems as well

Earth as a System The Earth system has two main energy sources - the sun and the earths interior The sun powers the external processes that occur in the atmosphere, hydrosphere, at at the surface Earths interior powers Earths inner processes, such as volcanoes and earthquakes A change in one of these systems can create changes in the other, and vice- versa.

What is Scientific Inquiry Section 5

Hypothesis Any scientist conducting an investigation follows a general procedure. First there must be a set of observations that needs to be explained In an effort to explain the observations, we come up with a hypothesis. A hypothesis is a possible explanation for a set of observations

Hypothesis are essentially educated guesses Before a hypothesis can be accepted by the scientific community, it must be thoroughly tested and analyzed. If a hypothesis is proven wrong by experiments, the scientist must go back and reformulate a new hypothesis, which must also be tested.

Theory Once a hypothesis has been repeatedly tested and supported, it becomes a theory A theory is a well tested and widely accepted belief that best explains certain observations Can a theory be changed?