Download Earth Science!!!!!! Chapter 1 – Intro to Earth Science Section 1.1

Earth Science!!!!!!
Chapter 1 – Intro to Earth Science
Section 1.1 – What is Earth Science?
+ Overview of Earth Science
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Earth science is the name for the group of sciences that deals with Earth and its
neighbors in space.
o Includes many subdivisions of geology: geochemistry, geophysics,
geobiology, paleontology, oceanography, meteorology, and astronomy
Geology
o means “ study of Earth”
o divided into two broad areas  physical geology and historical geology
 Physical geology – the examination of the materials that make up Earth
and the possible explanations for the many processes that shape our
planet.
 Processes like building mountains, causing earthquakes,
volcanoes, erosion by water, wind, and ice, etc.
 Historical Geology – tries to establish a timeline of the vast number of
physical and biological changes that have occurred in the past
o Oceanography – integrates the sciences of chemistry, physics, geology, and
biology
 Oceanographers study the composition and movements of seawater, as
well as coastal processes, seafloor topography, and marine life
o Meteorology – the study of the atmosphere and the processes that produce
weather and climate
o Astronomy – the study of the universe
 All objects in space, including Earth, are subject to the same physical
laws
+ Formation of Earth
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The nebular hypothesis suggests that the bodies of our solar system evolved from an
enormous rotating cloud called the solar nebula. It was made up mostly of hydrogen
and helium, with a small percentage of heavier elements.
o Figure 3 pg 4
Inner planets
o High temperatures
o Weak fields of gravity
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o Retained mostly heavy gases during formation
Outer planets
o Large in size and frigid temperatures
o Large amounts of water, ammonia, carbon dioxide, and methane
o A solar wind whisked away many of the lighter gases
Layers form on Earth
o The decay of radioactive elements, combined with heat released by colliding
particles produced some melting of the interior. So the denser elements sunk to
the core while the lighter elements were pushed to the top
o This sinking and floating is believed to still be happening
o Gases are released from the core during volcanic eruptions.
 The release of gases formed the atmosphere
Practice
1. How does physical geology differ from historical geology?
2. Describe the nebular hypothesis.
3. Explain why Earth is called a dynamic planet.
***Read Earth’s Place in the Universe
Section 1.2 - A View of Earth
+ Earth’s Major Spheres
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Four major spheres compose the physical environment
o Hydrosphere = the water portion of the planet
o Atmosphere = Earth’s gaseous envelope
o Geosphere = solid part of the Earth, below the atmosphere and oceans
o Biosphere = made up of all the life forms on Earth
 Biosphere interacts with all other major spheres
 The environment is characterized by the continuous interactions of air
and rock, rock and water, and water and air
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Hydrosphere
o Water is what makes Earth unique
o Water is constantly cycling between the oceans, and the atmosphere as it
evaporates and condenses
o 97% of the water on Earth is found in the oceans
o The other 3% is freshwater from lakes, streams, groundwater, and glaciers
 This 3% is responsible for sustaining life and creating many landforms
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Atmosphere
o Reaches beyond 100 kilometers above the Earth, but 90% occurs within just
16 kilometers of Earth’s surface.
o Protects us from the sun and gives us air to breath
o The constant interaction between space, the atmosphere and the Earth’s
surface give us climate
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Geosphere
o Because the geosphere is not uniform, it is divided into three main parts based
on differences in composition, the core, the mantle, and the crust
 ** figure 6 A pg 8
o The crust is not uniform in thickness, it is deepest beneath the continents and
shallower in the oceans
o The crust and outer mantle make up the lithosphere
 Figure 6B pg 8
o Below the lithosphere is the asthenosphere
 Rocks are partially molten at this level and can slowly flow because of
differing temperatures
o Beneath the asthenosphere is the lower mantle, where rocks are more dense
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Biosphere
o Plants and animals depend on the physical environment for life
o Organisms help maintain and alter their physical environment through
countless interactions
+Plate Tectonics
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Remember  Earth is a dynamic planet
Two types of forces affecting the Earth’s surface
o Destructive forces = such as weathering and erosion work to wear away high
points and flatten out the surface
o Constructive forces = such as mountain building and volcanism build up the
surface by raising the land and depositing new material in the form of lava
 Depend on Earth’s internal heat for energy
In the early 20th century, the idea that the continents had moved about the face of the
Earth
This began a period known as a revolution in our knowledge about Earth
The theory that finally emerged, called plate tectonics, provided geologists with a
model to explain how earthquakes and volcanic eruptions occur and how continents
move.
o This model shows that the lithosphere is divided into several individual
sections called plates
 **Figure 7 pg 9
o Plates move slowly and continuously across the surface
 Driven by uneven distribution of heat
o Creates earthquakes, volcanic activity, and the deformation of large masses
into mountains
Practice
1. What are the three main parts of the geosphere?
2. What sort of energy allows the tectonic plates to move?
3. Describe an example of how water moves through the hydrosphere.
4. Which of Earth’s spheres do each of these features belong?
a. Lake
b. Meadow
c. Canyon
d. Cloud
e. Mr. Schafer
Section 1.3 – Representing Earth’s Surface
+ Determining Location
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Global Grid
o Latitude is the distance north or south of the equator, measured in degrees.
Longitude is the distance east or west of the prime meridian measured in
degrees.
o Earth is 360 degrees in circumference
o The line of latitude around the middle of the globe is the equator. (0°)
o The primer meridian is the line longitudinal 0° marker
 Figure 8 pg 11
o Latitude and longitude form the global grid
 They also separate the Earth into hemispheres
Globes
o Present the shape and size of landforms and oceans in comparison to others
o Not practical for everyday use (finding addresses and street markings)
+ Maps and Mapping
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A map is a flat representation of Earth’s surface.
o Not all of Earth’s features can be accurately represented on a flat surface
without distortion
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No matter what kind of map is made, some portion of the surface will always look
either too small, too big, or out of place. Mapmakers have, however, found ways to
limit the distortion of shape, size, distance, and direction.
The Mercator Projection
o Gerardus Mercator created this map to help sailors navigate the world in 1569
 Figure 10 pg 12
 Although the sizes and distances were distorted it showed directions
accurately
 Still used today
Different Projection Maps for Different Purposes
o The best projection is determined by its intended use
o The Robinson Projection Map
 One of the most widely used
 Shows most distances, sizes and shapes accurately
 Much distortion is around the edge
 Figure 11 pg 13
o Conic Projection Map
 Made by wrapping a cone of paper around a globe at a particular line of
latitude
 Almost no distortion along the line of latitude used, but there can be
much distortion as you get further from that line of latitude
 Accuracy is great over a small area
 Used for road and weather maps
 Figure 12 pg 13
o Gnonomic Projections
 Made by placing a piece of paper on a globe so that it touches a single
point on the surface
 Distances and directions are distorted
 Used by sailors because they show the distance between two points
with great accuracy
 Figure 13 pg 13
+ Topographic Maps
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Topographic map = represents Earth’s three- dimensional surface in two dimensions
Topographic maps differ from the other maps discussed so far because topographic
maps show elevation. Topographical maps show elevation of Earth’s surface by
means of contour lines.
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Most also show bodies of water, roads, government and public buildings, political
boundaries, and place names
Useful for geologists, hikers, campers, and others interested in the lay of the land
Contour lines
o Indicates the elevation of the land
o Every position along the line is at the same elevation
o Adjacent lines show a change in elevation
o Every fifth line is bold and labeled with the elevation (known as an index
contour)
o Contour interval = tells the difference in elevation between adjacent contour
lines
 Lines close together represent steepness
 Lines far apart represent a gentler slope
 Figure 14, figure 15 pg 14
Scale
o A map represents a particular amount of area on Earth’s surface
o A map is drawn to scale where a certain distance on the map is equal to a
certain distance at the surface.
 Figure 16 pg 15 indicates a scale of 1:24,000
 This means that whatever the unit may be, 1 unit on the map is
equal to 24,000 units on the actual Earth
o Bar scale
 Allows you to measure a distance on the map with a ruler for
comparison
Geologic Maps
o = a map that shows the type and age of the rocks that are exposed, or crop out,
at the surface
o Shows identified rock formations along with their extent and distribution
o This type of map often has contour lines included
 Figure 16 pg 15
+ Advanced Technology
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Today’s technology provides us with the ability to more precisely analyze Earth’s
physical properties.
We have satellites and computers to do the work for us
Remote sensing = the process of collecting data about Earth from a distance (such as
from satellites)
o Useful for studying rivers, oceans, fires, pollution, natural resources, and many
other topics
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o Figure 17 pg 16
Global Positioning System (GPS)
o Provides maps in our cars or a handheld device for an instance description of
area, speed, location, direction, elevation, distance
o Very useful for tracking wildlife, navigation, studying earthquakes, measuring
erosion
o Table 1 pg 17
Practice
1. Describe the two sets of lines that are used on globes and some maps.
2. What is the purpose of contour lines on topographical maps?
3. What two lines mark zero degrees on the globe and what direction do they run?
4. Why is the Mercator projection map still used today?
Section 1.4 Earth System Science
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Looking at Earth as a dynamic planet with several interacting spheres is called Earth
system science. Its aim is to understand Earth as a system made up of numerous
interacting parts, or subsystems.
Tries to pull together knowledge from all branches of science to solve planet
problems
+ What is a System?
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A system can be any size group of interacting parts that form a complex whole.
Natural systems are usually driven by sources of energy that move matter and/or
energy from one place to another
Closed system = energy moves freely in and out of the system, but matter does not
enter or leave the system
Open system = both matter and energy flow into and out of the system
o Most natural systems are open systems
+ Earth as a System
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Two systems power the Earth:
1. the sun, which drives external processes that occur in the atmosphere, hydrosphere,
and at Earth’s surface
o Weather, climate, ocean circulation, erosion processes are driven by sun
energy
2. Earth’s interior is the second source of energy
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o Heat is present from the formation of the Earth and the decay of radioactive
elements
o Produce volcanoes, earthquakes, and mountains
Change in one part of Earth’s system will affect another part and/or the entire system
Changes in the system can cover great spans of distance and time
 Figure 18 pg 19
Our actions produce changes in all of the other parts of the Earth system
+ People and the Environment
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Environment refers to everything that surrounds and influences an organism
o Made up of living and nonliving factors
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 Nonliving factors (water, air, soil, rock) make up the physical
environment
Most of Earth science can be characterized as environmental science because most
research is conducted on the physical environment
Usually environmental science refers to the relationship between people and the
natural environment
 Figure 19 pg 20
Resources
o Water and soil, metallic, and nonmetal minerals
o Very important factor in Earth science
o Forms the foundation of modern civilization
o Earth science deals with occurrence and formation as well as maintaining
these supplies and the environmental impact of their use.
o Renewable resources can be replenished over relatively short spans of time.
 Ex: plants, animals, natural fibers, and forest products
 Ex: energy from water, wind, and sun are also considered renewable
o Nonrenewable resources are resources that continue to form, but the processes
that create them are so slow that it takes millions of years for significant
deposits to accumulate
 Ex: iron, aluminum, copper, and fuels: like oil, natural gas, and coal
Population
 Figure 20 pg 21
o Our population is growing at a rapid rate, and the rate of consumption of
natural resources is growing even faster.
 How will we compensate for these natural resources once they are
exhausted?
+ Environmental Problems
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Significant threats to the environment include air pollution, acid rain, ozone depletion,
and global warming.
o Humans cause several environmental problems
 Figure 21 pg 22
An understanding of the Earth is necessary for the location and recovery of basic
resources
As the population grows people will move to more and more dangerous areas to live
 Figure 22 pg 22
Practice
1. What are the two sources of energy that power Earth’s systems?
2. Compare and contrast open and closed systems.
3. Earth systems science is a particular way of looking at the Earth. Explain this.
Section 1.5 – What is Scientific Inquiry?
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Science is based on two assumptions
1. The natural world behaves in a consistent and predictable manner
2. Through careful, systematic study, we can understand and explain the natural
world’s behavior
- Scientific knowledge involves some basic steps
o First scientists collect data through observation and measurement
o These data are essential and are the starting point for developing new theories
+ Hypothesis
- Once data have been gathered, scientists try to explain how or why things happen in
the manner observed. Scientists do this by stating a possible explanation called a
scientific hypothesis
o More than one hypothesis may be developed for a given situation
o Just because a hypothesis is formed may not mean it is true
- Must be tested and analyzed
- Has to be able to be tested, or it is not scientifically useful
- Science is full of rejected hypotheses
o Ex: the Earth centered model of the universe, theory the Earth was flat
- “Science is a great many things, but in the end they all return to this: Science is the
acceptance of what works and the rejection of what does not.”
-Jacob Bronowski
+ Theory
- A scientific theory is well tested and widely accepted by the scientific community and
best explains certain observable facts
o Ex: the theory of plate tectonics provides the framework for understanding the
origin of continents and ocean basins, plus the occurrence of mountains,
earthquakes, and volcanoes
+ Scientific Methods
- The scientific method: the process of gathering facts through observations and
formulating theories and hypotheses
- Usually follows these steps:
1. The collection of scientific facts through observation and measurement
2. The development of one or more working hypotheses or models to explain
these facts
3. Development of observations and experiments to test the hypotheses
4. The acceptance, modification, or rejection of the hypothesis based on
extensive training
Practice:
1. Explain how a hypothesis can become a theory.
2. According to the scientific community, how does the natural world behave?
3. What happens if more than one hypothesis is put forward to explain the same
observations?