Transcript Slide 1

Earth Science
Table of Contents
Techniques used to learn about the earth…………………………………………………………….P.g. 3
Fossil evidence that illustrates how life forms evolve…………………………………………………P.g. 4
Techniques used to determine geological time scales…………………………………………………...P.g. 5
Factors responsible for earthquakes…………………………………………………………………P.g. 6
Factors responsible for volcanic eruption…………………………………………………………….P.g. 7
Factors responsible for mountain building……………………………………………………………P.g.8
Factors responsible for the formation of ocean ridges………………………………………………….P.g.9
A discussion of the theory of plate tectonics………………………………………………………….P.g.10
Describe the impact of volcanoes on the environment………………………………………………….P.g 11
Describe the impact of earthquakes on the environment……………………………………………....P.g.12
Bibliography…………………………………………………………………………………..…P.g. 13
Techniques used to learn about the earth
In addition to studying how life changes and diversifies over time, some evolutionary biologists are
trying to understand how life originated on Earth. This too requires the careful examination and interpretation of
many indirect clues. In one well-known series of experiments in 1953, American chemists Stanley L. Miller and
Harold C.. Urey attempted to reproduce the atmosphere of the primitive Earth nearly 4 billion years ago. They
circulated a mixture of gases believed to have been present at the time (hydrogen, methane, ammonia, and water
vapor) over water in a sterile glass container. They then subjected the gases to the energy of electrical sparks,
simulating the action of lightning on the primitive Earth. After about a week, the fluid turned brown and was
found to contain amino acids—the building blocks of proteins. Subsequent work by these scientists and others
also succeeded in producing nucleotides, the building blocks of DNA and other nucleic acids. While the artificial
generation of these molecules in laboratories did not produce a living organism, this research offers some support
that the first building blocks of life could have arisen from raw materials that were present in the environment of
the primitive Earth.
Fossil evidence that illustrates how life forms evolve
One way biologists learn about the evolutionary relationships between species is by examining
fossils. These ancient remains of living things are created when a dead plant or animal is buried under layers
of mud or sand that gradually turn into stone. Over time, the organism remains themselves may turn to
stone, becoming preserved within the rock layer in which they came to rest. By measuring radioactivity in
the rock in which a fossil is embedded, paleontologists (scientists who study the fossil record) can determine
the age of a fossil.
Fossils present a vivid record of the earliest life on Earth, and of a progression over time from
simple to more-complex life forms. The earliest fossils, for example, are those of primitive bacteria some 3.5
billion years old. In more recent layers of rock, the first animal fossils appear—primitive jellyfish that date
from 680 million years ago. Still more-complex forms, such as the first vertebrates (animals with backbones),
are documented by fossils some 570 million years old. Fossils also indicate that the first mammals appeared
roughly 200 million years ago.
Techniques used to determine geological time scales
Geologists have created a geological time scale to provide a common vocabulary for talking
about past events. The practice of determining when past geologic events occurred is called geochronology.
This practice began in the 1700s and has sometimes involved some personal and international disputes that
led to differences in terminology. Today the geologic time scale is generally agreed upon and used by
scientists around the world, dividing time into eons, eras, periods, and epochs. Every few years, the
numerical time scale is refined based on new evidence, and geologists publish an update.
Geologists use several methods to determine geologic time. These methods include physical
stratigraphy, or the placement of events in the order of their occurrence, and biostratigraphy, which uses
fossils to determine geologic time. Another method geologists use is correlation, which allows geologists to
determine whether rocks in different geographic locations are the same age. In radiometric dating, geologists
use the rate of decay of certain radioactive elements in minerals to assign numerical ages to the rocks.
Factors responsible for Earthquakes
The largest recorded earthquake in the world was a magnitude 9.5 (Mw) in Chile on May
22, 1960.
An earthquake is the sudden movement of the earth's surface by the release of energy in
the earth's crust and the crust of the earth bends slightly. Because the crust is so rigid, when the
pressure on the rocks becomes great the crust breaks and snaps into a new position, this is a vibration
known as a seismic wave. This seismic wave is the movement we call earthquakes.
In the areas where the crust has fracture when the to blocks of crust move against each
other and move in opposite direction, it is called faults. The crust of the earth bends slightly. But,
because the crust is rigid, when the stress or pressure exceeds the strength of the rocks, the crust breaks
and snaps into a new position. Vibrations called seismic waves are generated and travel both through
the earth and along its surface. These seismic waves cause the movement we call earthquakes. The
instrument used to measure the motion of the earth (magnitude) is called the seismometer. This records
how much energy is released during a earthquake. A Richter Magnitude is a scale used by scientists to
measures the Intensity of an earthquake.
Factors responsible for volcanic eruption
Volcanoes are mountains grow taller with time when they erupt. The molten rock,
magma, comes from inside the earth and erupts onto the surface. The period of time a volcano is
known to be active is unknown, because some seem to erupt forever. The volcano might be explosive
and produce ashes and lava. The explosions are usually first because there are lots of gases inside the
magma. . The most important gas is water, and then carbon dioxide. Sulfur dioxide, hydrogen
chloride, and hydrogen fluoride are emitted Once the magma is flat, a lava flow comes out. Once the
lava cools and hardens outside of the earth rocks are formed. Most volcanoes are 10,000 to 100,000
years old, and there are over 1, 500 actives volcanoes on the surface and 10, 000 underwater
volcanoes around the world. Indonesia is known to have the most volcanoes in the world.
Underwater volcanoes are very different from volcanoes above sea level because water has a higher
pressure then air. This higher pressure can cause explosive volcanic eruptions. Sometimes tiny islands
are formed from the debris of underwater volcanoes.
Interesting fact:
The biggest volcano known is the Mauna Loa, in Hawaii. It rises 29, 000 feet above the sea floor.
The oldest volcano known is Etna, it is about 350, 000 years old.
The word volcano originated from when Romans believed in Vulcan, the god of fire. They believed he
lived inside the earth beneath the island Hiera. It is now called Volcano and the word is used when
referring to any of the active volcanoes around the world.
Factors responsible for mountain building
When two pieces of the Earth's crust smash into each other the land is pushed
upwards, forming mountains. There are mountains under the surface of the earth, just like
volcanoes. Almost 80 per cent of our planet's fresh water originates in the mountains. As you
climb a mountain weather can change very quickly up mountains. In just a few minutes it can be
perfectly clear and then a thunder storm can, and in a few hours the temperatures can drop and
rise from hot temperatures to freezing temperatures. All mountains have one major characteristic in
common - climate, soil, vegetation over very short distances and rapid changes in altitude.
Interesting Facts:
The tallest 14 mountains in the world are the Himalayas, and measuring from sea level, Mount
Everest is the tallest. Mountains like these are useful because of there amazing scenery’s, the fresh
water and much more
Factors responsible for the formation of ocean ridges
These observations, along with many other studies of our planet, support the theory that
underneath the Earth's crust (the lithosphere: a solid array of plates) is a malleable layer of heated
rock known as the asthenosphere. The heated layer of rock (that heats up the hot springes, and the
raw material that pushes up the mid ocean ridges and forms new ocean floor) pushes upwards to the
ocean ridges that produces the opposite flow of magma and pull apart the sea floor. As the floor
spreads the crack in the ridges let in the molten lava to the surface to form the newest ocean floor.
This new ocean floor will eventually come in contact with the continental plates and will be
supressed underneath the continent. This cycle will repeat over and over until.
A discussion of the theory of plate tectonics
The story of Plate Tectonics is a exciting story of continents drifting
swiftly from place to place breaking apart, colliding, and grinding against each other;
of terrestrial mountain ranges rising up; of oceans opening and closing and undersea
mountain chains girdling the planet; of violent earthquakes and fiery volcanoes. Plate
Tectonics describes the intricate design of a complex, living planet in a state of
dynamic flux.
There are nine large plates and a number of smaller plates. While
most plates are comprised of both continental and oceanic crust the giant Pacific
Plate is almost entirely oceanic, and the tiny Turkish-Aegean Plate is entirely
land. Of the nine major plates, six are named for the continents embedded in
them: the North American, South American, Eurasian, African, IndoAustralian, and Antarctic. The other three are oceanic plates: the Pacific, Nazca,
and Cocos.
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Describe the impact of volcanoes on the environment
Volcanic eruptions come in all sizes: small, medium, large, extra large, giant economy size,
and super huge size. Giant eruptions can literally affect the whole world. On the other hand, small
eruptions may affect only a single hillside or valley.
The impact of volcanoes on people or the land are very severe and devastating.
Obviously if you don’t get out of the way of moving lava, ash or mud you can be buried alive.
Volcanoes lava can travel up to speeds of 50-60 kmh. Also, Volcanoes are very difficult to farm
on. At Pinatubo, it has been recently realized that the huge amount of ash deposited high on
the slopes (where very few people live) has since the main eruption caused way more damage to
the lower areas (where people DO live) than the original eruption did. So, as you can see there
are many impacts on the environment form volcanoes.
Describe the impact of earthquakes on the environment
The impact of earthquakes on the environment can be very destructive
and deadly. Earthquakes can topple buildings, demolish houses and stores, and most
of all they can kill. After an earthquake not to many people want to do anything,
like go out and continue their normal life again. Everybody is scared of an
aftershock or another earthquake.
Most people
believe that
the
movement of
plate
tectonics are
what start
earthquakes