Earth Science [PDF]

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13PrinciplesofSterile Technique 1. Only sterile items are used within the sterile field.2. Sterile persons are gowned and gloved.3. Tables are sterile only at table level.4. Sterile persons touch only sterile items or areas. Unsterile persons touch onlyunsterile items or areas.5. Unsterile persons avoid reaching over sterile field. Sterile persons avoid leaning overunsterile areas.6. Edges of anything that encloses sterile content are considered unsterile.7. Unsterile persons avoid sterile areas.8. Sterile field is created as close as possible to the time of use.9. Sterile areas are continuously kept in view.10. Sterile persons keep well within sterile area.11. Sterile persons keep contact with sterile areas to a minimum.12. Microorganisms must be kept to irreducible minimum.13. Destruction of integrity of microbial barriers results in contamination.



What Is Earth Science?



Credit: NASA



“Earth science” is a broad term that encompasses four main branches of study, each of which is further broken down into more specialized fields.



Geology Geology is the study of the substances that make up the Earth, the processes that shape it, and of how these materials and processes have changed the Earth over time. Geology is very important as everything we do depends on our relationship to the planet we live on. Two important subfields of geology are vulcanology (the study of volcanoes), and seismology (the study of earthquakes). Understanding these processes can help enable us to predict and mitigate the effects of natural disasters such as volcanic eruptions, major quakes, tsunamis and landslides. Geologists are also at the forefront of the quest for natural resources such as oil, natural gas, and other raw materials. Advertisement Hydrologists study the availability and distribution of the Earth’s freshwater resources including both surface water and aquifers. Physical geography is the study of the Earth’s landforms. Paleontologists are interested in Earth’s history. Geologists may work for industry, government agencies, universities or other settings. Most geologists do field work at least part of the time.



Meteorology



Meteorology is the study of Earth’s atmosphere and how changes in temperature, air pressure, humidity and winds affect the weather. Perhaps more than any other science, meteorology is concerned with using data to make predictions of future events. Broadcast meteorologists are probably the most familiar; men and women who interpret and report weather data on television or radio to inform the public and protect us when severe weather threatens. Forensic meteorologists often work for lawyers or insurance agencies. Their job is to determine how weather conditions may have contributed to accidents or caused damage to property. Climatologists study the large-scale weather patterns for a given region over long periods of time. Meteorologists and climatologists work closely with other scientists to determine the possible effects of global climate change and whether human activities are affecting global temperatures.



Oceanography Oceanography, or marine science, is the interdisciplinary study of the sea. Oceanographers may study currents, storms or waves. Oceanographers may use sophisticated technology to map the ocean floor or evaluate whether movement of subsea tectonic plates might cause rifting and tsunami waves. Oceanographers are frequently biologists who seek to understand and protect marine ecosystems. It is said that we know more about the surface of the moon than we do about the oceans of our own world. Earth has more oceans than land environments, and the seas may hold the keys to energy and food resources. We desperately need more information to protect the oceans while we are using them for our own survival. Oceanographers may work for governments, for the fishing or energy industries, or shipping concerns. Most oceanographers travel a lot and should enjoy working on the water. [Photos: Hawaii's New Underwater Volcano]



Astronomy Astronomy is the study of Earth’s neighbors in the solar system and beyond. Optical astronomy is direct observation of the visible universe using a variety of telescopes and visual probes such as the Hubble Space Telescope. Radio astronomy can detect radiation from wavelengths well beyond the visible spectrum, but they must also have enormous “dishes” to collect the radio waves. In the past these size limitations made the enormous radio telescopes cumbersome and difficult to aim. Today with the modern ability to link radio telescopes almost instantly by using computer technology, there are many more applications for this science. Astronomers are making discoveries about the size, composition, energy and evolution of distant stars and galaxies. Planetologists study the planets of our solar system and beyond. Space probes send photos and data from distant systems. In our own solar system the robot probe Curiosity crawls the surface of Mars to analyze soil samples and transmit data to Earth. Cosmologists seek to understand the origin of the universe. Most astronomers work for government space agencies or universities. The Earth sciences, studying the impact that humans have on the Earth and how natural processes affect us, provide vital information for our future as a species. Our future depends on understanding how the Earth can provide food, water and energy for our growing population. Perhaps one day we will be able to apply these lessons to inhabit another planet as well.



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Earth sciences WRITTEN BY: 



Claude C. Albritton







Brian Frederick Windley See Article History



Earth sciences, the fields of study concerned with the solid Earth, its waters, and the air that envelops it. Included are the geologic, hydrologic, and atmospheric sciences. The broad aim of the Earth sciences is to understand the present features and the past evolution of the Earth and to use this knowledge, where appropriate, for the benefit of humankind. Thus the basic concerns of the Earth scientist are to observe, describe, and classify all the features of the Earth, whether characteristic or not, to generate hypotheses with which to explain their presence and their development, and to devise means of checking opposing ideas for their relative validity. In this way the most plausible, acceptable, and long-lasting ideas are developed. The physical environment in which humans live includes not only the immediate surface of the solid Earth, but also the ground beneath it and the water and air above it. Early man was more involved with the practicalities of life than with theories, and thus his survival depended on his ability to obtain metals from the ground to produce, for example, alloys, such as bronze from copper and tin, for tools and armour, to find adequate water supplies for establishing dwelling sites, and to forecast the weather, which had a far greater bearing on human life in earlier times than it has today. Such situations represent the foundations of the three principal component disciplines of the modern Earth sciences. The rapid development of science as a whole over the past century and a half has given rise to an immense number of specializations and subdisciplines, with the result that the modern Earth scientist, perhaps unfortunately, tends to know a great deal about a very small area of study but only a little about most other aspects of the entire field. It is therefore very important for the layperson and the researcher alike to be aware of the complex interlinking network of disciplines that make up the Earth sciences today, and that is the purpose of this article. Only when one is aware of the marvelous complexity of the Earth sciences and yet can understand the breakdown of the component disciplines is one in a position to select those parts of the subject that are of greatest personal interest. It is worth emphasizing two important features that the three divisions of the Earth sciences have in common. First is the inaccessibility of many of the objects of study. Many rocks, as well as water and oil reservoirs, are at great depths in the Earth, while air masses circulate at vast heights above it. Thus the Earth scientist has to have a



good three-dimensional perspective. Second, there is the fourth dimension: time. The Earth scientist is responsible for working out how the Earth evolved over millions of years. For example, what were the physical and chemical conditions operating on the Earth and the Moon 3.5 billion years ago? How did the oceans form, and how did their chemical compositionchange with time? How has the atmosphere developed? And finally, how did life on Earth begin, and from what did man evolve? Today the Earth sciences are divided into many disciplines, which are themselves divisible into six groups: 1. Those subjects that deal with the water and air at or above the solid surface of the Earth. These include the study of the water on and within the ground (hydrology), the glaciers and ice caps (glaciology), the oceans (oceanography), the atmosphere and its phenomena (meteorology), and the world’s climates (climatology). In this article such fields of study are grouped under the hydrologic and atmospheric sciences and are treated separately from the geologic sciences, which focus on the solid Earth. 2. Disciplines concerned with the physical-chemical makeup of the solid Earth, which include the study of minerals (mineralogy), the three main groups of rocks (igneous, sedimentary, and metamorphic petrology), the chemistry of rocks (geochemistry), the structures in rocks (structural geology), and the physical properties of rocks at the Earth’s surface and in its interior (geophysics). 3. The study of landforms (geomorphology), which is concerned with the description of the features of the present terrestrial surface and an analysis of the processes that gave rise to them. 4. Disciplines concerned with the geologic history of the Earth, including the study of fossils and the fossil record (paleontology), the development of sedimentary strata deposited typically over millions of years (stratigraphy), and the isotopic chemistry and age dating of rocks (geochronology). 5. Applied Earth sciences dealing with current practical applications beneficial to society. These include the study of fossil fuels (oil, natural gas, and coal); oil reservoirs; mineral deposits; geothermal energy for electricity and heating; the structure and composition of bedrock for the location of bridges, nuclear reactors, roads, dams, and skyscrapers and other buildings; hazards involving rock and mud avalanches, volcanic eruptions, earthquakes, and the collapse of tunnels; and coastal, cliff, and soil erosion. 6. The study of the rock record on the Moon and the planets and their satellites (astrogeology). This field includes the investigation of relevant terrestrial features— namely, tektites (glassy objects resulting from meteorite impacts) and astroblemes (meteorite craters).



With such intergradational boundaries between the divisions of the Earth sciences (which, on a broader scale, also intergrade with physics, chemistry, biology, mathematics, and certain branches of engineering), researchers today must be versatile in their approach to problems. Hence, an important aspect of training within the Earth sciences is an appreciation of their multidisciplinary nature. Brian Frederick Windley