DOCSLIB.ORG

Earth Space Science : 08 Our Solar System : 08.00 Our Solar System Pretest

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Earth Space Science : 08 Our Solar System : 08.00 Our Solar System Pretest Earth Space Science : 08 Our Solar System : 08.00 Our Solar System Pretest Our Solar System Pretest Our solar system is our neighborhood within a vast universe. And just as in any city, we're not the only neighborhood around. The Milky Way galaxy has many solar systems, just as the universe has many galaxies. Let's look at how our solar system got its start. The solar system was formed about four and a half billion years ago when a cloud of gases and dust became compacted. At the center a star was born, the sun, which contains more than 99 percent of the solar system's mass. The dust that orbited the sun agglomerated to form planets, including Earth, as well as millions of other celestial bodies such as asteroids and comets. The solar system has a total diameter of twelve billion kilometers. Every solar system was brought together by the same force—gravity. Gravity plays a tremendous role in the universe. Whether it is involved in forming suns and planets or influencing the structure and stability of solar systems, there is much to learn about the effects of gravity. With gravity and millions of years, particles of matter can come together in space. As gas molecules and dust particles move closer to one another, the gravitational pull between them increases. Little by little, the mass adds up and increases the rate at which matter assembles. It eventually groups into large gas and dust clouds called nebulas, which are birthplace for stars and their solar systems. Consider the anchoring phenomenon for this module: Gravity is a pivotal force in the birth, development, motion, and interactions of objects within our solar system. It is also this same force of gravity that caused a lot of chaotic bombardment in the early formation of the objects in the solar system. This module will focus on these driving questions: • What models, theories, and tools have scientists used to understand our solar system and its formation? • How have forces played a role in the development of our solar system, and how do they allow us to represent and predict planetary motion? • What are the properties of the objects in our solar system, and how do those properties help us understand the age and formation of objects in the solar system? • How do Earth, the sun, and the moon interact to form a system that creates observable phenomena? Earth Space Science : 08 Our Solar System : 08.01 Formation of Our Solar System Objectives How have ideas about our solar system changed over time? At the end of this lesson, you will be able to: • explain the formation of the planetary system in our solar system • explain how the work of scientists has shaped our views of the solar system • compare models of our solar system over time • identify different methods of measuring astronomical distances and apply them in various scenarios Gazing into the night sky, ancient people explained astronomical events in terms of religion and philosophy. With the European Renaissance, scientific and religious explanations for astronomical events diverged. As the distinctions between science and religion became clearer, scientists increasingly used scientific instruments to make astronomical observations. Imagine you could travel backward in time and talk to scientists from the past. The scientists would tell you about two different models of the solar system. Use the activity below to place a “call” to two important scientists from the past: Call between Ptolemy and Copernicus Sound of dialing followed by ringing followed by a phone being answered Ptolemy: Hello, this is Claudius Ptolemy. Student: Hello. I’m a student in an Earth space science class in the 21st century. Can you tell me what you think about astronomy and our solar system? Ptolemy: Oh, yes, I have lots of ideas about the solar system. I even wrote books about the topic. Student: Really? Where does Earth fit into the solar system? Ptolemy: Why, that’s an easy one! Earth is the center. When you look at the sky at night, you can see all the stars moving around Earth. Therefore, Earth is at the center. Student: Thank you. I have another call to make. It was nice talking to you. Sound of phone being hung up, followed by new dialing, ringing, and another phone being answered Student: Hello, may I speak to Nicolaus Copernicus? Copernicus: This is he. What can I do for you? Student: I understand you lived during the scientific revolution that happened during Europe’s Renaissance. Can you tell me anything about the location of Earth within the solar system? Copernicus: Indeed, I can. I have taken many observations and I have concluded that the sun is the center of the solar system. Student: Really? I heard differently? Copernicus: Well, sometimes science builds on both the accomplishments and mistakes of the past. I am convinced my model is the correct view of the solar system. Student: Thank you. I appreciate your time. Sound of phone being hung up Our Solar System In 1977, NASA launched two unmanned space probes, Voyager 1 and Voyager 2, to explore our solar system and beyond. Answer: The probes have been travelling for more than 30 years, and they still have not reached the very outer limits of the solar system, as most scientists define it. However, the probes did pass the outermost planets in 1989. Solar System: The Sun: The sun is the star in our solar system that provides warmth and light to the planets. The Planets: Planets are objects that orbit a star. A planet is massive enough to have gravity of its own but not massive enough to ignite. Moon: Moons are objects that orbit planets. Comet: One of the small objects in our solar system that orbit the sun. Small Bodies: Many objects not big enough to be planets orbit the sun. These objects include comets, asteroids, and meteorites. Each will be described in more detail in a subsequent lesson in this module. The Universe: The universe includes all galaxies, stars, dust, gases, planets, and space. Our solar system is a very tiny fraction of the size of the universe. Distances In Space: Distances in space can be measured using a variety of units. For large distances, a light year is often used. For distances within the solar system, the astronomical unit is often used. One AU equals 150 million kilometers, Earth's average distance from the sun. (Because the distance between Earth and the sun changes throughout the year, it is more appropriate to speak of Earth's average distance from the sun, which is approximately 149,597,871 kilometers. For simplicity's sake, this number is rounded up to 150 million kilometers, or 93 million miles). The solar system does not simply stop at a certain point. It's a bit like a city, where the edges are hard to define. Because the outer boundary of the solar system is not clearly defined, it's difficult to say how big the solar system is. Its size can be measured from a region beyond Pluto's orbit where the sun's influence greatly decreases and interstellar space begins. The region encompassed from the sun to this boundary is called the heliosphere, as shown in the image below: As you can see, the heliosphere is very large. The solar system occupies only a small part of the heliosphere. Let's estimate the size of the solar system by imagining the sun on a scale you can easily visualize. The sun is approximately 1.4 million kilometers in diameter. To create our scale model of the solar system, think about the sun as being the size of a basketball (78 centimeters in diameter). Using this scale, Earth's diameter would be only 7 millimeters. Using this same scale, the distance to Pluto would be about 3,300 meters. If a basketball on your desk represented the sun, then by the same scale you would have to walk more than 2 miles to reach Pluto! Calculating of AU: How many kilometers are represented by 155 AU? To calculate the answer, complete the following activity: Calculation of AU Step 1 1 AU = 150,000,000 km This is the conversion factor used to determine the answer. This is a known value. Calculation of AU Step 2 155 AU = x km To calculate the number of kilometers in 155 AU, set up the following equation. The unknown portion of the equation is the number of kilometers. Calculation of AU Step 3 155 AU 150,000,000 km /1AU = x km Now use the conversion factor to convert AU to kilometers. Because 1 AU is equal to 150 million kilometers, that ratio can be substituted into the equation. Calculation of AU Step 4 155 AU 150,000,000 km /1AU = 23,250,000,000 km Multiplying the number of AU by the conversion factor gives the correct answer. Practice This One On Your Own: How many AU are represented by 480 million kilometers? The History of Solar System Models Claudius Ptolemy: Ptolemy wrote a book that contained the key astronomical ideas of the time. From about 150 AD, his model dominated scientific thought. He thought the solar system was geocentric—the planets and sun travel around Earth in “epicycles,” or large perfectly circular orbits. His model is also known as the Ptolemaic view of the solar system. Prior to Ptolemy, other ancient philosophers, such as Aristotle, also suggested the universe was geocentric, but Ptolemy was the first to explain this model in detail. Nicolaus Copernicus: Copernicus is considered the father of modern astronomy.
Load more

Recommended publications
  • Modern Astronomical Optics - Observing Exoplanets 2
    Modern Astronomical Optics - Observing Exoplanets 2. Brief Introduction to Exoplanets Olivier Guyon - [email protected] – Jim Burge, Phil Hinz WEBSITE: www.naoj.org/staff/guyon → Astronomical Optics Course » → Observing Exoplanets (2012) Definitions – types of exoplanets Planet (& exoplanet) definitions are recent, as, prior to discoveries of exoplanets around other stars and dwarf planets in our solar system, there was no need to discuss lower and upper limits of planet masses. Asteroid < dwarf planet < planet < brown dwarf < star Upper limit defined by its mass: < 13 Jupiter mass 1 Jupiter mass = 317 Earth mass = 1/1000 Sun mass Mass limit corresponds to deuterium limit: a planet is not sufficiently massive to start nuclear fusion reactions, of which deuterium burning is the easiest (lowest temperature) Lower limit recently defined (now excludes Pluto) for our solar system: has cleared the neighbourhood around its orbit Distinction between giant planets (massive, large, mostly gas) and rocky planets also applies to exoplanets Habitable planet: planet on which life as we know it (bacteria, planets or animals) could be sustained = rocky + surface temperature suitable for liquid water Formation Planet and stars form (nearly) together, within first few x10 Myr of system formation Gravitational collapse of gas + dust cloud Star is formed at center of disk Planets form in the protoplanetary disk Planet embrios form first Adaptive Optics image of Beta Pic Large embrios (> few Earth mass) can Shows planet + debris disk accrete large quantity of
    [Show full text]
  • Curriculum Vitae - 24 March 2020
    Dr. Eric E. Mamajek Curriculum Vitae - 24 March 2020 Jet Propulsion Laboratory Phone: (818) 354-2153 4800 Oak Grove Drive FAX: (818) 393-4950 MS 321-162 [email protected] Pasadena, CA 91109-8099 https://science.jpl.nasa.gov/people/Mamajek/ Positions 2020- Discipline Program Manager - Exoplanets, Astro. & Physics Directorate, JPL/Caltech 2016- Deputy Program Chief Scientist, NASA Exoplanet Exploration Program, JPL/Caltech 2017- Professor of Physics & Astronomy (Research), University of Rochester 2016-2017 Visiting Professor, Physics & Astronomy, University of Rochester 2016 Professor, Physics & Astronomy, University of Rochester 2013-2016 Associate Professor, Physics & Astronomy, University of Rochester 2011-2012 Associate Astronomer, NOAO, Cerro Tololo Inter-American Observatory 2008-2013 Assistant Professor, Physics & Astronomy, University of Rochester (on leave 2011-2012) 2004-2008 Clay Postdoctoral Fellow, Harvard-Smithsonian Center for Astrophysics 2000-2004 Graduate Research Assistant, University of Arizona, Astronomy 1999-2000 Graduate Teaching Assistant, University of Arizona, Astronomy 1998-1999 J. William Fulbright Fellow, Australia, ADFA/UNSW School of Physics Languages English (native), Spanish (advanced) Education 2004 Ph.D. The University of Arizona, Astronomy 2001 M.S. The University of Arizona, Astronomy 2000 M.Sc. The University of New South Wales, ADFA, Physics 1998 B.S. The Pennsylvania State University, Astronomy & Astrophysics, Physics 1993 H.S. Bethel Park High School Research Interests Formation and Evolution
    [Show full text]
  • Chapter 16 the Sun and Stars
    Chapter 16 The Sun and Stars Stargazing is an awe-inspiring way to enjoy the night sky, but humans can learn only so much about stars from our position on Earth. The Hubble Space Telescope is a school-bus-size telescope that orbits Earth every 97 minutes at an altitude of 353 miles and a speed of about 17,500 miles per hour. The Hubble Space Telescope (HST) transmits images and data from space to computers on Earth. In fact, HST sends enough data back to Earth each week to fill 3,600 feet of books on a shelf. Scientists store the data on special disks. In January 2006, HST captured images of the Orion Nebula, a huge area where stars are being formed. HST’s detailed images revealed over 3,000 stars that were never seen before. Information from the Hubble will help scientists understand more about how stars form. In this chapter, you will learn all about the star of our solar system, the sun, and about the characteristics of other stars. 1. Why do stars shine? 2. What kinds of stars are there? 3. How are stars formed, and do any other stars have planets? 16.1 The Sun and the Stars What are stars? Where did they come from? How long do they last? During most of the star - an enormous hot ball of gas day, we see only one star, the sun, which is 150 million kilometers away. On a clear held together by gravity which night, about 6,000 stars can be seen without a telescope.
    [Show full text]
  • The Solar System Cause Impact Craters
    ASTRONOMY 161 Introduction to Solar System Astronomy Class 12 Solar System Survey Monday, February 5 Key Concepts (1) The terrestrial planets are made primarily of rock and metal. (2) The Jovian planets are made primarily of hydrogen and helium. (3) Moons (a.k.a. satellites) orbit the planets; some moons are large. (4) Asteroids, meteoroids, comets, and Kuiper Belt objects orbit the Sun. (5) Collision between objects in the Solar System cause impact craters. Family portrait of the Solar System: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, (Eris, Ceres, Pluto): My Very Excellent Mother Just Served Us Nine (Extra Cheese Pizzas). The Solar System: List of Ingredients Ingredient Percent of total mass Sun 99.8% Jupiter 0.1% other planets 0.05% everything else 0.05% The Sun dominates the Solar System Jupiter dominates the planets Object Mass Object Mass 1) Sun 330,000 2) Jupiter 320 10) Ganymede 0.025 3) Saturn 95 11) Titan 0.023 4) Neptune 17 12) Callisto 0.018 5) Uranus 15 13) Io 0.015 6) Earth 1.0 14) Moon 0.012 7) Venus 0.82 15) Europa 0.008 8) Mars 0.11 16) Triton 0.004 9) Mercury 0.055 17) Pluto 0.002 A few words about the Sun. The Sun is a large sphere of gas (mostly H, He – hydrogen and helium). The Sun shines because it is hot (T = 5,800 K). The Sun remains hot because it is powered by fusion of hydrogen to helium (H-bomb). (1) The terrestrial planets are made primarily of rock and metal.
    [Show full text]
  • The Maunder Minimum and the Variable Sun-Earth Connection
    The Maunder Minimum and the Variable Sun-Earth Connection (Front illustration: the Sun without spots, July 27, 1954) By Willie Wei-Hock Soon and Steven H. Yaskell To Soon Gim-Chuan, Chua Chiew-See, Pham Than (Lien+Van’s mother) and Ulla and Anna In Memory of Miriam Fuchs (baba Gil’s mother)---W.H.S. In Memory of Andrew Hoff---S.H.Y. To interrupt His Yellow Plan The Sun does not allow Caprices of the Atmosphere – And even when the Snow Heaves Balls of Specks, like Vicious Boy Directly in His Eye – Does not so much as turn His Head Busy with Majesty – ‘Tis His to stimulate the Earth And magnetize the Sea - And bind Astronomy, in place, Yet Any passing by Would deem Ourselves – the busier As the Minutest Bee That rides – emits a Thunder – A Bomb – to justify Emily Dickinson (poem 224. c. 1862) Since people are by nature poorly equipped to register any but short-term changes, it is not surprising that we fail to notice slower changes in either climate or the sun. John A. Eddy, The New Solar Physics (1977-78) Foreword By E. N. Parker In this time of global warming we are impelled by both the anticipated dire consequences and by scientific curiosity to investigate the factors that drive the climate. Climate has fluctuated strongly and abruptly in the past, with ice ages and interglacial warming as the long term extremes. Historical research in the last decades has shown short term climatic transients to be a frequent occurrence, often imposing disastrous hardship on the afflicted human populations.
    [Show full text]
  • A Review on Substellar Objects Below the Deuterium Burning Mass Limit: Planets, Brown Dwarfs Or What?
    geosciences Review A Review on Substellar Objects below the Deuterium Burning Mass Limit: Planets, Brown Dwarfs or What? José A. Caballero Centro de Astrobiología (CSIC-INTA), ESAC, Camino Bajo del Castillo s/n, E-28692 Villanueva de la Cañada, Madrid, Spain; [email protected] Received: 23 August 2018; Accepted: 10 September 2018; Published: 28 September 2018 Abstract: “Free-floating, non-deuterium-burning, substellar objects” are isolated bodies of a few Jupiter masses found in very young open clusters and associations, nearby young moving groups, and in the immediate vicinity of the Sun. They are neither brown dwarfs nor planets. In this paper, their nomenclature, history of discovery, sites of detection, formation mechanisms, and future directions of research are reviewed. Most free-floating, non-deuterium-burning, substellar objects share the same formation mechanism as low-mass stars and brown dwarfs, but there are still a few caveats, such as the value of the opacity mass limit, the minimum mass at which an isolated body can form via turbulent fragmentation from a cloud. The least massive free-floating substellar objects found to date have masses of about 0.004 Msol, but current and future surveys should aim at breaking this record. For that, we may need LSST, Euclid and WFIRST. Keywords: planetary systems; stars: brown dwarfs; stars: low mass; galaxy: solar neighborhood; galaxy: open clusters and associations 1. Introduction I can’t answer why (I’m not a gangstar) But I can tell you how (I’m not a flam star) We were born upside-down (I’m a star’s star) Born the wrong way ’round (I’m not a white star) I’m a blackstar, I’m not a gangstar I’m a blackstar, I’m a blackstar I’m not a pornstar, I’m not a wandering star I’m a blackstar, I’m a blackstar Blackstar, F (2016), David Bowie The tenth star of George van Biesbroeck’s catalogue of high, common, proper motion companions, vB 10, was from the end of the Second World War to the early 1980s, and had an entry on the least massive star known [1–3].
    [Show full text]
  • Astr-Astronomy 1
    ASTR-ASTRONOMY 1 ASTR 1116. Introduction to Astronomy Lab, Special ASTR-ASTRONOMY 1 Credit (1) This lab-only listing exists only for students who may have transferred to ASTR 1115G. Introduction Astro (lec+lab) NMSU having taken a lecture-only introductory astronomy class, to allow 4 Credits (3+2P) them to complete the lab requirement to fulfill the general education This course surveys observations, theories, and methods of modern requirement. Consent of Instructor required. , at some other institution). astronomy. The course is predominantly for non-science majors, aiming Restricted to Las Cruces campus only. to provide a conceptual understanding of the universe and the basic Prerequisite(s): Must have passed Introduction to Astronomy lecture- physics that governs it. Due to the broad coverage of this course, the only. specific topics and concepts treated may vary. Commonly presented Learning Outcomes subjects include the general movements of the sky and history of 1. Course is used to complete lab portion only of ASTR 1115G or ASTR astronomy, followed by an introduction to basic physics concepts like 112 Newton’s and Kepler’s laws of motion. The course may also provide 2. Learning outcomes are the same as those for the lab portion of the modern details and facts about celestial bodies in our solar system, as respective course. well as differentiation between them – Terrestrial and Jovian planets, exoplanets, the practical meaning of “dwarf planets”, asteroids, comets, ASTR 1120G. The Planets and Kuiper Belt and Trans-Neptunian Objects. Beyond this we may study 4 Credits (3+2P) stars and galaxies, star clusters, nebulae, black holes, and clusters of Comparative study of the planets, moons, comets, and asteroids which galaxies.
    [Show full text]
  • Kinematics of Planet-Host Stars and Their Relation to Dynamical Streams in the Solar Neighbourhood
    A&A 461, 171–182 (2007) Astronomy DOI: 10.1051/0004-6361:20065872 & c ESO 2006 Astrophysics Kinematics of planet-host stars and their relation to dynamical streams in the solar neighbourhood A. Ecuvillon1,G.Israelian1, F. Pont2,N.C.Santos2,3,4, and M. Mayor2 1 Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain e-mail: [email protected] 2 Observatoire de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland 3 Centro de Astronomia e Astrofisica de Universidade de Lisboa, Observatorio Astronomico de Lisboa, Tapada de Ajuda, 1349-018 Lisboa, Portugal 4 Centro de Geofisica de Évora, Rua Romaõ Ramalho 59, 7000 Évora, Portugal Received 21 June 2006 / Accepted 28 August 2006 ABSTRACT We present a detailed study on the kinematics of metal-rich stars with and without planets, and their relation to the Hyades, Sirius and Hercules dynamical streams in the solar neighbourhood. Accurate kinematics have been derived for all the stars belonging to the CORALIE planet search survey. We used precise radial velocity measurements and CCF parameters from the CORALIE database, and parallaxes, photometry and proper motions from the HIPPARCOS and Tycho-2 catalogues. The location of stars with planets in the thin or thick discs has been analysed using both kinematic and chemical constraints. We compare the kinematic behaviour of known planet-host stars to the remaining targets belonging to the volume-limited sample, in particular to its metal-rich population. The high average metallicity of the Hyades stream is confirmed. The planet-host targets show a kinematic behaviour similar to that of the metal-rich comparison subsample, rather than to that of the comparison sample as a whole, thus supporting a primordial origin for the metal excess observed in stars with known planetary companions.
    [Show full text]
  • Oil, Earth Mass and Gravitational Force
    A peer reviewed version is published at: https://doi.org/10.1016/j.scitotenv.2016.01.127 Oil, Earth mass and gravitational force Khaled Moustafa Editor of the Arabic Science Archive (ArabiXiv) E-mail: [email protected] Highlights Large amounts of fossil fuels are extracted annually worldwide. Would the extracted amounts represent any significant percentage of the Earth mass? What would be the consequence on Earth structure and its gravitational force? Modeling the potential loss of Earth mass might be required. Efforts for alternative renewable energy sources should be enhanced. Abstract Fossil fuels are intensively extracted from around the world faster than they are renewed. Regardless of direct and indirect effects of such extractions on climate change and biosphere, another issue relating to Earth’s internal structure and Earth mass should receive at least some interest. According to the Energy Information Administration (EIA), about 34 billion barrels of oil (~4.7 billion metric tons) and 9 billion tons of coal have been extracted in 2014 worldwide. Converting the amounts of oil and coal extracted over the last 3 decades and their respective reserves, intended to be extracted in the future, into mass values suggests that about 355 billion tons, or ~ 5.86*10−9 (~ 0.0000000058) % of the Earth mass, would be ‘lost’. Although this is a tiny percentage, modeling the potential loss of Earth mass may help figuring out a critical threshold of mass loss that should not be exceeded. Here, I briefly discuss whether such loss would have any potential consequences on the Earth’s internal structure and on its gravitational force based on the Newton's law of gravitation that links the attraction force between planets to their respective masses and the distances that separate them.
    [Show full text]
  • Good Science, Bad Science: Teaching Evolution in the States. INSTITUTION Thomas B
    DOCUMENT RESUME ED 447 099 SP 039 576 AUTHOR Lerner, Lawrence S. TITLE Good Science, Bad Science: Teaching Evolution in the States. INSTITUTION Thomas B. Fordham Foundation, Washington, DC. PUB DATE 2000-09-00 NOTE 66p. AVAILABLE FROM Thomas B. Fordham Foundation, 1627 K Street, N.W., Suite 600, Washington, DC 20006; Tel: 202-223-5452 or 888-TBF-7474 (toll-free); Fax: 202-223-9226; Web site: http://www.edexcellence.net. PUB TYPE Reports Descriptive (141) EDRS PRICE MF01/PC03 Plus Postage. DESCRIPTORS *Academic Standards; Biological Influences; Creationism; Elementary Secondary Education; *Evolution; Public Schools; *Science Education; *State Standards ABSTRACT This report discusses evolution in science education, evaluating the state-by-state treatment of evolution in science standards. It explains the role of evolution as an organizing principle for all the historical sciences. Seven sections include: "Introduction" (the key role of evolution in the sciences); "How Do Good Standards Treat Biological Evolution?" (controversial versus consensual knowledge and why students should learn about evolution); "Extrascientific Issues" (e.g., the diversity of anti-evolutionists, why anti-evolutionism persists, and how science standards reflect creationist pressures); "Evaluation of State Standards" (very good to excellent, good, satisfactory, unsatisfactory, useless or absent, and disgraceful); "Sample Standards"; "Further Analysis" (grades for science standards as a whole); and "Conclusions." Overall, 31 states do at least a satisfactory job of handling the central organizing principle of the historical sciences, 10 states do an excellent or very good job of presenting evolution, and 21 states do a good or satisfactory job. More than one-third of states do not do a satisfactory job.
    [Show full text]
  • Physics 100: Homework 5 Solutions 1) Somewhere Between the Earth
    Physics 100: Homework 5 Solutions 1) Somewhere between the Earth and the moon, the gravitational force on a space shuttle would cancel. Is this location closer to the moon or to the Earth? Explain your answer. The gravitational force on the shuttle due to the moon is proportional to the shuttle’s mass, the moon’s mass, and inversely proportional to the square of the shuttle-moon distance. That due to the Earth is proportional to the shuttle’s mass, the Earth’s mass, and inversely proportional to the square of the shuttle-Earth distance. Since Earth mass >> moon mass, the shuttle must be much closer to the moon in order for the two attractions to cancel. 2) Which is greater, the gravitational pull of the moon on the Earth or that of the sun on the Earth? Which has a greater effect on our ocean tides, the sun or the moon? Explain your answers. The gravitational pull of the Sun on the Earth is greater than the gravitational pull of the Moon, about 180 times as large due its much greater mass, as explained in class. The tides, however, are caused by the differences in gravitational forces by the Moon on opposite sides of the Earth. The difference in gravitational forces by the Moon on opposite sides of the Earth is greater than the corresponding 2 difference in forces by the stronger pulling but much more distant Sun. The difference, 1/(d+Dearth) – 2 1/d , where Dearth is the diameter of Earth, is greater for the moon (smaller d) than it is for the sun (larger d), which is the math-way of saying what we said in class about the inverse-law flattening out… 3 a) A particular atom contains 47 electrons, 61 neutrons, and 47 protons.
    [Show full text]
  • A Summary and Analysis of Twenty-Seven Years of Geoscience Conceptions Research Kim A
    Commentary: A Summary and Analysis of Twenty-Seven Years of Geoscience Conceptions Research Kim A. Cheek1 ABSTRACT Seventy-nine studies in geoscience conceptions appeared in peer-reviewed publications in English from 1982 through July 2009. Summaries of the 79 studies suggest certain recurring themes across subject areas: issues with terms, scale (temporal and spatial), role of prior experience, and incorrect application of everyday knowledge to geoscience phenomena. The majority of studies reviewed were descriptive and employed only one method of data collection and response type. Eleven-fourteen-year-olds and university undergraduates were most commonly represented in the samples. A small percentage of studies of geoscience conceptions of K-12 students made reference to standards documents or a curriculum as justification for the research design. More directed descriptive studies, along with greater parity between descriptive and intervention studies is needed. Greater attention to developmental theories of concept acquisition, national standards documents, and intersection with cognitive science literature are warranted. INTRODUCTION students to erroneous conclusions about geoscience Research into students’ conceptions in science has phenomena. Much of the research on student conceptions been going on for several decades. There is a large body of of geologic time and plate tectonics has been conducted scientific conceptions literature, though there is since her review. It is important to determine whether her comparatively less in the geosciences than in other earlier conclusions apply to newer research and novel scientific disciplines (Libarkin, S. Anderson, Science, topics. Dove did not discuss methodologies of the studies Beilfuss, & Boone, 2005; Dodick & Orion, 2003a). she reviewed. With the research base that has developed Nevertheless, a substantial body of research into students’ in the eleven years since her review, a discussion of geoscience conceptions has appeared within the past methodological trends is warranted.
    [Show full text]