Earth S cience Review Unit 1:

Earth Science Review Unit 1: Unit 1: Earth’s Materials

Introduction to Earth Science: Earth’s Materials Earth Science includes; among others sciences, geology, oceanography, meteorology, astronomy. • Geologymeans “study of the Earth” :Geology is divided into two areas: Physical geology & Historical geology • Physical geologyincludes the examination of the materials that makeup Earth and the possible explanations for the many processes that shape our planet. • Historical geology’saim is to understand the Earth’s long history of these processes. Historical geology is concerned with establishing timelines of the vast amount of changes, both physical and biological, that have occurred on the Earth over the course of time. • Oceanography integrates the sciences of chemistry, physics geology and biology to study the composition and movements of seawater, as well as coastal processes, seafloor topography, and marine life. • Meteorology is the scientific study of the atmosphere and the processes that produce weather and climate. • Astronomy is the study of the Universe which includes Earth’s position in relation to the Universe.

Introduction to Earth Science: Earth’s Materials Nebular hypothesis: The nebular hypothesis suggests that the bodies of our solar system evolved from an enormous rotating cloud called a solar nebula. ________________________________________________________ Earth’s Formation • Shortly after Earth formed, the decay of radioactive elements, combined with heat released by colliding particles, producing some melting of it’s interior. • This allowed the denser elements, mostly iron and nickel, to sink to Earth’s center because of gravity. The less dense rocky components floated outward toward the surface. This sinking and floating is believed to be still be going on, but on a much smaller scale. As a result, the Earth’s interior is not made up of uniform material. It consists instead of layers of differing materials.

Introduction to Earth Science: Earth’s Materials • Earth is divided into 4 major spheres: hydrosphere, atmosphere, geosphere, biosphere. • All the water on Earth makes up the hydrosphere. • The atmosphere is the life sustaining, thin, gaseous envelope that surrounds the Earth. • The Geosphere is composed of the Earth’s rocks and minerals. • Earth’ s biosphere includes all life on Earth.

Introduction to Earth Science: Earth’s Materials • Earth’s core is the region in the Earth’s center that is composed primarily of iron-nicklealloy. It is divided into two sections: Outer core & Inner core • Earth’s Inner Core: Is a sphere having a radius of 1220 km. Despite high temperatures, the tremendous pressure compresses the inner core to a solid state of iron-nickle. • Earth’s outer core: Is a liquid layer about 2260 km thick composed of flowing iron-nickle. The flow of metallic iron in this zone creates the Earth’s magnetic fields.

Introduction to Earth Science: Earth’s Materials Earth’s mantle is the layer that links the Earth’s crust to the Earth’s outer core. Earth’s mantle is divided into two parts • Upper mantle: extends from about 70 kilometers to 700 km • Lower mantle: extends from about 700 km to 2900 km

Introduction to Earth Science: Earth’s Materials Representing Earth’s Surface: Maps • In addition to accurate data, mapmakers need a precise way to describe the exact location of land features. Mapmakers use a global grid to help determine location. Global grid lines are made up of lines called latitude and longitude. The distance around the Earth is measured in degrees. • Latitude is the distance north or south from the equator. Longitudeis the distance East or West from the prime Meridian. • The equator is an imaginary line running around the Earth’s middle that cuts the Earth into two hemispheres; the northern and southern hemisphere. • The Prime Meridian and 180 degree meridian (the International date line) divide the earth into Eastern and Western hemispheres.

Introduction to Earth Science: Earth’s Materials Different types of map projection systems were invented for different purposes: 4 main types all have strengths and weaknesses • On a Mercator projection map, the lines of longitude and latitude are parallel on this map making it easier to show direction accurately. The drawback to these maps is that sizes and distances become distorted. • Robinson projection maps show most distances, sizes and shapes accurately but have distortions, specially around the edges of the maps. • Conic projection maps are made by wrapping a cone of paper around the globe at a particular line of latitude. There is almost no distortion along the line of latitude that is in contact with the cone but distortion increases as one moves away from the line. • Gnomonic projections are made by touching a piece of paper on a globe so that it touches a single point on the globe’s surface. Various points and lines are than projected on the map. Although distances and directions are distorted, these maps are useful to sailors as they show with great accuracy the shortest distance between two points.

Introduction to Earth Science: Earth’s Materials • Topographic maps represent Earth’s three-dimensional surface in 2D. • Topographic maps use contour lines to show changes in elevation. Every position along a contour line is the same elevation is the same elevation. The contour interval is the distance between the contour lines. • A map scale is a ratio. One inch on a map may represent 10 miles on a map or a hundred miles. The map scale gives you the key to understand and determine real world distances from a map. ________________________________________________________ Matter:Everything in the Universe is made of matter. On Earth, matter exists usually in three states • Solid: definite shape such as rocks • Liquid: definite volume but no definite shape • Gas: neither definite shape nor definite volume • An element is a substance that can not be broken down into simpler substances by chemical or physical means. • An atom is the smallest particle of matter that contains the characteristics of an element.

Introduction to Earth Science: Earth’s Materials • Protonsare dense particles with positive electrical charges. Electronshave negative charges and are smaller. Neutronsare equally as dense as protons but have no charge. • Most atoms have the same number of protons and electrons balancing out their charge to a neutral charge. • Atoms with the same number of protons but different numbers of neutrons are isotopes of an element. • Chemical combinations of the atoms of elements are called compounds. A compound is a substance that consists of two or more elements that are chemically combined in specific proportions. • An atom that has an electric charge because of a gain or loss of one or more electrons is called an ion. • Covalent bondsform when atoms share electrons (rather than pass off an electron).

Introduction to Earth Science: Earth’s Materials • A mineral is a naturally occurring, inorganic solid with an orderly crystalline structure and a definite chemical composition. • Materials must possess 5 major characteristics to be considered a mineral: Naturally occurring, Solid substance, Orderly crystalline structure, Definite chemical composition, Inorganic in makeup • Magma is molten rock that forms deep within the Earth. • There are four major processes by which minerals form: • Crystallization from magma • Precipitation • Changes in pressure and temperature • Formation from hydrothermal solutions • There are six main mineral groups: Silicates, Carbonates, Oxides, Sulfates, sulfides, Halides, Native elements

Introduction to Earth Science: Earth’s Materials • Carbonates are minerals that contain the elements carbon, oxygen, and one or more other metallic elements. • Oxides are minerals that contain oxygen and one or more other elements. • Sulfates and sulfides are minerals that contain the element sulfur. • Halides are minerals that contain a halogen ion plus one or more other elements. • Native Elementsare minerals that only contain one element or type of atom.

Introduction to Earth Science: Earth’s Materials • 8 main characteristics are used to identify and differentiate mineral groups from each other: Color, Streak, Luster, Crystal form, Hardness, Cleavage, Fracture, Density • Streak is the color of a mineral in it’s powdered form. • Luster is used to describe how light is reflected from the surface of a mineral. • Crystal Form is the visible expression of a mineral’s internal arrangement of atoms. • Hardness is the measure of resistance of a mineral to being scratched. • Fractureis the uneven breakage of a mineral. • Cleavageis the tendency of a mineral to break, or cleave, along flat, even surfaces. • Density is the ratio of an object’s mass to it’s volume.

Introduction to Earth Science: Earth’s Materials • A rock is any solid mass of mineral or mineral-like matter that occurs naturally as part of our planet. • Rocks are classified into three groups based on how they were formed: Igneous Rocks, Sedimentary Rocks, Metamorphic Rocks • Interactions among Earth’s water, air, and land can cause rocks to change from one type to another. The continuous process that causes rocks to change makes up the rock cycle.

Introduction to Earth Science: Earth’s Materials • When magma cools and hardens beneath the surface or as a result of a volcanic eruption, igneous rocks form. • Eventually sediments are compacted and cemented to form sedimentary rocks. • Under extreme pressure and temperature conditions, sedimentary rock will change into metamorphic rock. • Heat from Earth’s interior and energy from the sun power the rock cycle.

Introduction to Earth Science: Earth’s Materials • Rocks that form when magma hardens beneath earth’s surface are called intrusive igneous rocks • When lava hardens, the rocks that form are called extrusive igneous rocks. • Erosion involves weathering and the removal of rock. When an agent of weathering; water, wind, ice, or gravity, loses energy, it drops the sediments. This process is called deposition. • Compactionis a process that squeezes, or compacts, sediments. • Cementationtakes place when dissolved minerals are deposited in the tiny spaces among the sediments.

Introduction to Earth Science: Earth’s Materials • Just like igneous rocks, sedimentary rocks can be classified into two main groups according to the way they form; clastic sedimentary and chemical sedimentary. • During contact metamorphism, hot magma moves into rocks. • Regional metamorphism results in large-scale deformation and high grade-metamorphism. • The agents of metamorphism are heat, pressure and hydrothermal solutions • Metamorphic rocks can be classified by texture as foliated or nonfoliated

Introduction to Earth Science: Earth’s Materials Alternative Sources of Energy • A renewable resource can be replenished over fairly short time spans, whereas a nonrenewable resource takes millions of years to form and accumulate. • Fossil fuels include coal, oil, and natural gas. • Solar energy has two advantages; the fuel is free and it’s nonpolluting. • In nuclear fission, the nuclei of heavy atoms such as uranium-235, are bombarded with neutrons. The uranium nuclei split into smaller nuclei and emit neutrons and heat energy.

Introduction to Earth Science: Earth’s Materials Alternative Sources of Energy • Some experts estimate that in the next 50 to 60 years, wind power could provide between 5 to 10% of the country’s demand for electricity. • The water held in a reservoir behind a dam is a form of hydroelectric energy that can be released through the dam to produce electric power. • Hot water, from geothermal sources, is used directly for heating and to turn turbines to generate electric power.

Introduction to Earth Science: Earth’s Materials

Earth S cience Review Unit 1: