Science final exam

• Latitude


  Imaginary lines that go west to east
• Equator


  Located at zero degrees latitude
• Longitude


  Imaginary lines that go from north to south
• Prime meridian


  Located in Greenwich, England at zero degrees longitude
• Landform


  A natural formation or area of land
• Landforms


  • Mountains
• Water always flows downhill because of gravity
• Topographic map


  Shows the physical features of an area of land including elevation
• Layers of the earth


  • Inner Core
  • Outer Core
  • Mantle
  • Crust
• Density determines the layers of the earth
• Convection currents


  The ability of the asthenosphere to flow
• When mantle rocks near the core heat up, they become less dense than the cooler, upper mantle rocks. These warmer rocks rise while the cooler rocks sink
• Theory of continental drift


  Proposed by Alfred Wegner in 1912 that continents fit together like a puzzle and moved slowly to their current locations, forming the supercontinent PANGEA
• Evidence for continental drift


  • Reptile Fossil clues
  • Plant fossil clues
  • Climate
  • Rocks
  • Geologic Formations
  • Puzzle Like Fit
• Divergent plate boundary


  Plates move away from each other, magma rises and creates new crust, forms mid-ocean ridge (seafloor spreading), space between plates is called a rift valley
• Convergent collision plate boundary

  Plates are the same density which is why they push up to make mountains, forms a single land mass (e.g. Himalayan Mountains)
• Convergent subduction plate boundary


  Oceanic plate goes under continental plate because it is more dense, deep-sea trench is formed (e.g. Mariana Trench)
• Transform plate boundary


  Plates move side to side against each other, increased friction causes faults (e.g. San Andreas Fault)
• Fault


  Breaks or cracks in the crust along which movement has occurred
• Normal fault


  Forms due to tension, rock is pulled apart, footwall moves up and hanging wall moves down
• Reverse fault


  Forms due to compression, rocks pushed together, hanging wall moves up and footwall moves down
• Strike-slip fault


  Plates move past each other, hanging wall and footwall move horizontally to each other
• Earthquake


  A sudden release in built up stress between rocks along a fault, earthquakes release energy
• Epicenter


  Point at the surface that is directly above the beginning of the quake
• Focus


  The area beneath the earth's surface where the rock that is under stress breaks and causes the earthquake
• Types of earthquake waves

  • P Waves
  • S Waves
  • Surface Waves
• P waves will always arrive first, they are the fastest wave, Push together and pull apart the materials they pass through, Travels through solids, liquids, and gasses
• Surface waves cause the most damage, Caused by P and S waves trapped near the surface, Travel along surfaces, Causes rolling, up and down movement
• Aftershock


  Smaller earthquakes after the big earthquake, dangerous because they can last for days or weeks and cause more damage
• TsunamiCaused by earthquakes, volcanic eruptions or landslides which cause a large displacement of water, travels fast over long distances losing little energy, dangerous because it can destroy everything in its path, cause flooding, loss of life, and there is very little warning time
• Volcano


  A weak spot in the crust where molten material or magma comes to the surface, magma is composed of melted rock, gases and water from the mantle, when magma reaches the surface it is called lava, located where plates are diverging or converging
• Hot spot


  A stationary area where material from deep within the mantle rises and then melts to create magma, Hawaiian Islands formed over millions of years as the Pacific Plate drifted over the hot spots
• Features of magma that determine type of eruption

  • Amount of water vapor or other gases
  • Silica content of the magma
• Quiet eruption


  Basaltic magma, shield volcano
• Explosive eruption


  Granitic and andesitic magma, composite and cinder cone volcanoes
• Viscosity of magma

  • Low silica content: Gas easily escapes, quiet eruption, basaltic lava
  • High silica content: Gas bubbles are trapped, explosive eruption, andesitic and granite lava
• Types of volcanoes


  • Shield Volcanoes
  • Cinder Cone Volcanoes
  • Composite Volcanoes
• The amount of silica determines how explosive the volcano is, high silica magmas are thicker so they trap gases which leads to a more explosive eruption, low silica magmas allow gas to escape so they have quiet and calm eruptions
• Pyroclastic flow


  High density mixture of hot ash, rock fragments, hot gases that destroys everything in its path, usually has a lower flow of coarse fragments along the ground and a cloud of ash above
• Hazards of volcanic ash


  • Breathing Problems
  • Engine Problems for cars and airplanes
  • Collapses roofs
  • ash can irritate eyes, skin, and lungs