PRELIM EXAM IN EARTH SCIENCE

• The Big Bang Theory


  A rapid expansion of the universe
• Matter could not exist at that time
• Fundamental forces

  • Gravity (Attraction between bodies)
  • Electromagnetic force (binds atoms into molecules)
  • Strong nuclear force (binds protons and neutrons together in the nucleus)
  • Weak nuclear force (breaks down an atom's nucleus and produces radioactive decay)
• 3 minutes later of continuously expanding

  It cool down
• Temperatures became cool enough for H and He atoms to completely form. At that point, photon escaped.

  300,000 years later
• After 300 million years


  1. Stars and galaxies began to form H and He with the aid of gravity

  2. The overall composition of the universe transitioned from light elements to heavier elements from supernova as temperature cooled down

  3. This made solid particles, in the form of nebula, to exist
• Nebulae


  Would later form the star system and planets know today
• Steady State Theory


  Fred Hoyle, Thomas Gold, and Hermann Bondi predicted a universe that expanded but did not change its density
• Oscillating theory


  Alan Guth, known as Cyclic model, a variant of Big Bang theory in which it is suggested that the universe passes through successive cycles of expansion and contraction (or collapse). At the end of collapse phase, with the universe packed into a small volume of great density, it is possible that a bounce would occur.
• Some believe that at some stage in the future, the Universe will stop expanding and begin to contract
• Encounter Theory


  According to the encounter hypothesis, about 5 Gya, a Rogue star passed close to the sun and stripped materials (hot gases) from both the sun and Rogue star. The hot gases continued to spin in the same direction as the sun, and coalesced into smaller lumps which formed the planets.
• Proto planet Hypothesis


  The proto planet hypothesis suggests that about 5 billion years ago a great cloud of gas and dust rotated slowly in space. The cloud was at least 10 billion kilometers in diameter. As time passed, the cloud shrank under the pull of its own gravitation or was made to collapse by the explosion of a passing star. Most of the cloud's material gathered around its own center. Its shrinking made it rotate faster, like a spinning whirlpool. The compression of its material made its interior so hot that a powerful reaction, hydrogen fusion, began and the core of the cloud blazed into a newborn sun. About 10 percent of the material in the cloud formed a great plate-like disk surrounding the sun far into space. Friction within the disk caused most of its mass to collect in a number of huge whirlpools or eddies. These eddies shrank into more compact masses called proto planets and later formed planets and moons. Some uncollected material remains even today as comets, meteoroids, and asteroids
• Nebular Hypothesis


  States that the entire Solar System started as a large cloud of gas that contracted due to self- gravity. The solar nebular hypothesis describes the formation of our solar system from a nebula cloud made from a collection of dust and gas. It is believed that the sun, planets, moons, and asteroids were formed around the same time around 4.5 billion years ago from a nebula.
• The Earth System


  System- a set of components that are interrelated. Earth's Major Subsystems - atmosphere, lithosphere, hydrosphere, biosphere
• Earth's Major Subsystems

  • atmosphere (blanket of air that surrounds the earth)
  • lithosphere (sphere of the solid crust including rocks, landforms)
  • hydrosphere (system of water including rivers, subsoil water and atmospheric water)
  • biosphere (sphere of life including plants and animals)
• Minerals


  • Naturally occurring
  • Inorganic
  • Solid
  • Definite chemical composition
  • Ordered internal structure
• Minerals

  • Mercury
  • Glaciers/Ice
  • Sulphur
  • Diamond
• Mineral


  Natural solid usually formed as crystals that are found in rocks
• Rock


  Natural solid made of one or more minerals
• Many of the useful substances we get from the Earth's crust are minerals, which can contain useful metals and other substances
• Uses of minerals

  • Aluminum - to make wires, cans, car and airplane parts, and sports equipment
  • Calcite - to make cement and concrete for buildings, sidewalks, and bridges
  • Copper - to make wire
  • Halite (salt) - to make food taste better, to preserve food, to melt ice on roads and walkways
  • Iron - to make steel for cars, ships, buildings, tools, appliances
• Crystal form


  • The external expression of the internally ordered arrangement of atoms
• Hardness


  The ability of a mineral to resist abrasion or scratching on its surface
• Mohs Mineral Hardness Scale

  • Talc
  • Gypsum
  • Calcite
  • Flourite
  • Apatite
  • Feldspar
  • Quartz
  • Topaz
  • Corundum
  • 10) Diamond
• Testing mineral hardness. The harder mineral (quartz) scratches the softer one (calcite)
• Luster


  How light is reflected from the surface of a mineral
• Luster types


  • Metallic
  • Vitreous
  • Waxy
  • Pearly
  • Earthy
• Color


  Determined by how the crystals absorb and reflect light. Although color is easy to recognize, it is often not reliable as a property
• Colored varieties of calcite

  • Crystal
• Streak


  The color of a mineral's powdered form left behind after it is scraped or rubbed across a porcelain streak plate
• Hematite (Fe2O3) can have various colors, but its streak is always red-brown
• Cleavage


  The tendency of some minerals to break (cleave) along flat, parallel surfaces
• Cleavage directions

  • Muscovite Mica - 1 direction
  • Potassium Feldspar - 2 directions at 90º
  • Amphibole - 2 directions NOT at 90º
  • Halite - 3 directions at 90º
  • Calcite - 3 directions NOT at 90º
• Fracture


  The mineral breaks in no consistent manner
• Specific gravity


  The weight or heaviness of a mineral, expressed as the ratio of the mineral's weight to an equal volume of water
• Silicates


  • Composed of silicon-oxygen tetrahedrons, an arrangement which contains four oxygen atoms surrounding a silicon atom (SiO4-4)
  • Feldspar, Quartz, Biotite, and Amphibole are the most common silicates
• Halides


  • Halite (NaCl), Flourite (CaF2)
• Carbonates


  • Calcite (CaCO3), Dolomite (CaMg(CO3)2)
• Oxides


  • Hematite (Fe2O3), Magnetite (Fe3O4), Corundum (Al2O3), Ice (H2O)
• Sulfates


  • Barite, Gypsum