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50+ Earth Science Facts that will help you pass the mid-term exam

(these are not the only things you need to know, but they will certainly help)

  1. Metric System uses factors of 10.† Meter for length, Gram for mass, Liter for volume
    Kilo    Hecta    Deka    meter     deci    centi    milli
    If converting within the metric system all you have to do is move the decimal place over
  2. 3 methods knowledge acquired in science - Observation, measurement and inference.† Measurement is the most objective
  3. The formula for density is D=m/v
  4. The same substance always has the same density.
  5. According to the Protoplanet Hypothesis the solar system began as a rotating cloud of dust and gas that condensed and Earth originated about 5 billion years ago.† The evidences are
    All planets revolve around the sun in the same direction
    Most planets revolve around the sun on the same axis
    There is still left over material in the solar system (meteors and comets)
  6. The best model of the earth's shape is a sphere. 3 pieces of evidence
    shadow of earth on the moon during a lunar eclipse is spherical
    position of the stars rotate slowly during the course of the night
    mast of a ship will appear first over the horizon when a ship is traveling towards you.
  7. The true shape of the earth is an OBLATE SPHEROID.
  8. To determine the earth's circumference, the altitude of the sun at TWO locations is needed.
  9. Latitude lines go east-west, just like the equator, but measure distances north or south.
  10. Longitude is based on observations of the sun.
  11. Longitude lines go north-south, but measure distances east or west.
  12. The altitude of Polaris equals your latitude.
  13. Mercator maps show lines of longitude and latitude crossing at right angles, but distort land masses in the higher latitudes.
  14. The difference between true north and magnetic north varies with latitude and is called magnetic declination.
  15. The closer isolines (contour-isobar-isotherm) are, the steeper the slope or gradient.
  16. Contour lines point upstream when crossing a stream.
  17. Refracting telescopes only use lenses, reflecting telescopes use at least one mirror in combination with a lens.
  18. Power of a telescope depends upon the radius of the objective mirror or lens.
  19. As wavelength increases the frequency decreases.
  20. Higher the frequency the warmer the object, because more frequency means more energy.†
  21. All the energies of the electromagnetic spectrum travel at the same speed (speed of light) in waves.
  22. The red shift of light is an indication that the star is moving away from us.
  23. The universe began with a big explosion--"The Big Bang" about 13-15 billion years ago.
  24. Hertzsprung-Russell Diagram compares temperature and luminosity (absolute magnitude) of stars, and color is directly related to temperature.
  25. Red Giants are cooler stars than white dwarfs.
  26. A starís light is produced by the nuclear fusion of hydrogen atoms into helium.† This is true for our Sun too.
  27. Our solar system is located on one of the outer arms of our Milky Way Galaxy, a spiral galaxy.
  28. The Sun is a main sequence star, a stable state; and is expected to become a red giant then a white dwarf.
  29. Sunspots are cooler areas on the Sunís surface, and go through a cycle every 11 years.†
  30. As you move away from the Sunís core the layers become cooler, with the odd exception of the corona.
  31. Rotation: turning on an axis
  32. Revolution: movement of one body around another other = orbit
  33. Planets APPEAR to go backwards (retrograde) as the earth passes them in space.
  34. Geocentric: Earth centered (proposed by Ptolemy);† Heliocentric: sun centered (proposed by Copernicus)
  35. Galileo was first to use a telescope to view the sky, and found evidence for the heliocentric model of the solar system Ė the phases of Venus and 4 moons of Jupiter
  36. The closer a planet is to the sun the higher its velocity
  37. The farthest distance of a planet from the sun is the aphelion.
  38. According to Keplerís First Law, all orbits of planets are ellipses, and the more ďovalĒ the more eccentric the orbit
  39. Keplerís 2nd Law is the Equal Areas Law, and is used to determine speed
  40. Keplerís 3rd Law is used to determine a planetís distance to the Sun or its period of revolution.
  41. Newtonís Law of Universal Gravitation states that the gravitation force between 2 objects is directly related to the mass and distance between the 2 objects.
  42. Astronomical Unit is the Earthís average distance from the Sun, approximately 150 million kilometers.
  43. Our solar system contains 9 planets, their satellites, comets and asteroids.
  44. Inner planets aka Terrestrial Planets have a rocky crust, denser mantle layer, very dense core, smaller in size, and fewer moons.
  45. Outer planets aka Jovian or Gas Planets are much larger, gaseous, much less dense, colder, and have rings and more moons.
  46. Comets have highly eccentric orbits, are composed of ice and rock with tails that point away from the Sun due to solar wind.
  47. Asteroids are rock/metal that mostly inhabit the space between the Inner and Outer Planets.
  48. Meteors occur when meteoroids enter the Earthís atmosphere, and meteorites occur only when they strike the Earthís surface.
  49. Foucault's pendulum and the coriolis effect prove the earth rotates

50. FOUCAULT'S PENDULUM: appears to change its direction of swing.

51. Summer solstice is June 21st

  1. Winter solstice is December 21st
  2. Earth is closest to the sun in January.
  3. Equator always has 12 hours of daylight.
  4. Equinoxes: March 21st† and September 23rd
  5. The earth revolves counterclockwise (365ľ days).
  6. The earth rotates west to east (24 hours).
  7. The lower the altitude of the sun, the longer shadows it casts.
  8. Vertical rays (overhead sun) can only occur between 23 1/2oN (Tropic of Cancer) and 23 1/2oS (Tropic of Capricorn)
  9. Earthís axis is tilted 23 1/2o to the ecliptic plane.
  10. The period from one full moon to the next is 29.5 days, but the time it takes for the moon to fully revolve around the Earth is 27.3 days.
  11. The moon has phases because of the angle at which we view its surface (Remember though: half is always lit).
  12. Waxing is the increase of the Moonís lighted surface; waning is the decrease of the lighted surface
  13. Earth can only view the same side of the moon regardless of the phase because the moon rotates at exactly the same speed it revolves around the Earth.
  14. Tides are caused by the gravitational pull of the moon and sun; with 2 high and 2 low tides occurring each 24 hour period.
  15. Spring tides only occur during new and full moons, neap tides occur at quarter moons.
  16. Lunar eclipse only occurs during full moon and is visible to more of the Earth than a solar eclipse.
  17. Solar eclipse only occurs during new moon.