Earth Science

1. Earth Science

2. 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

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

8. 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

9. 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.

10. 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, Indo-Australian, and Antarctic. The other three are oceanic plates: the Pacific, Nazca, and Cocos.

11. 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.

12. 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