Transcript Earth Science 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.
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Geology means “study of the Earth” :Geology is divided into two areas:
Physical geology & Historical geology
Physical geology includes the examination of the materials that makeup
Earth and the possible explanations for the many processes that shape our
planet.
 Historical geology’s aim 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.
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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.
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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.
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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.
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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
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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
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Earth’s core is the region in the Earth’s center that is
composed primarily of iron-nickle alloy. 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
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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. Longitude is
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.
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Matter: Everything in the Universe is made of matter. On Earth,
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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
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Protons are dense particles with positive electrical charges. Electrons
have negative charges and are smaller. Neutrons are 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 bonds form when atoms share electrons (rather than pass off
an electron).
Introduction to Earth Science: Earth’s Materials
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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
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Magma is molten rock that forms deep within the Earth.
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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
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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 Elements are minerals that only contain one element or type of
atom.
Introduction to Earth Science: Earth’s Materials
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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
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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.
Fracture is the uneven breakage of a mineral.
Cleavage is 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
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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
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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.
 Compaction is a process that squeezes, or compacts, sediments.
 Cementation takes 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