Chapter 1 Introduction to Earth Science Earth Science is the name for the group of sciences that studies Earth and its neighbors in space. It includes Geology, which is the study of the Earth. It deals a lot with the rocks of Earth and the changing of Earth. Oceanography is the study of Earth’s oceans. Meteorology is the study of the atmosphere and the processes that produce weather and climate. Astronomy is the study of the universe.

The Earth formed billions of years ago The Earth formed billions of years ago. It formed from the solar nebula, which was a huge cloud of dust and gas in space that gave rise to the Sun and all the planets. The two most abundant elements were hydrogen and helium. This is called the Nebular Theory.

Section 1.2: A View of the Earth The Earth has four major spheres, which include: The Atmosphere is the life sustaining thin gaseous envelope that surrounds Earth. The Hydrosphere is all the water on Earth. The Geosphere is the mostly solid part of the Earth itself. It is divided into three main parts, the crust, mantle, and core. The Biosphere includes all of the life on Earth.

The Theory of Plate Tectonics Earth is a dynamic planet, which means it is always changing. Earth’s crust is broken into plates that move, which generates earthquakes, volcanic activity, mountain bulilding, etc. We will discuss this in greater detail later.

Section 1.3 Representing Earth’s Surface We determine location on Earth by using Latitude and Longitude. Latitude is the distance north or south of the equator, measured in degrees. The equator is 0 degrees latitude and splits the Earth into two equal hemispheres. The North Pole is 90 degrees North in latitude, while the South Pole is 90 degrees South in latitude. Longitude is the distance east or west of the prime meridian, measured in degrees. The Prime Meridian is 0 degrees longitude, and it runs through Greenwich, England. The International Date Line is 180 degrees longitude and is on the opposite side of the Prime Meridian.

The grid pattern created by Longitude and Latitude

Representing the Globe using Maps Mercator Projections make all lines parallel, including longitude. This greatly distorts the polar regions, making them look much larger than they actually are. This map is widely used by sailors.

Representing the Globe using Maps Robinson Projections show most distances, sizes, and shapes accurately, but there still is distortion around the edges. They are very useful in seeing all of the Earth at once.

Representing the Globe using Maps A Conic Projection is commonly used to make road and weather maps. They are drawn by wrapping a cone of paper around a particular line of latitude. Very accurate over small areas.

Representing the Globe using Maps Gnomonic Projections are drawn from a single point, usually from one of the poles. They show the shortest distance between two points on the globe, known as the great circle route. These maps are used for navigation by airplanes.

Representing the Globe using Maps Topographic maps represent Earth’s 3-D surface in 2-D. These maps show elevation using contour lines. A contour line indicates the elevation of the land. The distance between two contour lines is the contour interval. Every fifth contour line is bolder and labeled with elevation. This is an index contour.

Representing the Globe using Maps Hachure lines indicate depressions or sink holes. Scale represents the relationship between distance on a map and the actual distance on Earth’s surface. Satellite images create highly accurate maps. GPS, or Global Positioning System, provides maps in our cars and phones that guide us to our destinations.

Section 1.4 Earth System Science Earth is a system made up of numerous interacting parts and subsystems. The sun drives external processes that occur in the atmosphere, hydrosphere, and at Earth’s surface. Earth’s interior is also a source of energy. Human actions produce changes in all other parts of the Earth’s systems. Renewable energy sources can be replenished. Nonrenewable energy sources take millions of years to be replaced. Threats to the environment include air pollution, acid rain, ozone depletion, and global climate change.

Section 1.5 Scientific Inquiry A hypothesis is a scientific explanation for a set of observations that can be tested in ways that support or reject it. Testing is usually done by experimentation. Variables are factors that are changed in an experiment. The independent variable is the only you actually change. The dependent variable is the one that you measure. A theory is a well established, highly reliable explanation of natural or physical phenomenon. A law is a concise, specific statement that summarizes a pattern found in nature. Example – Law of Gravity