scie

• Volcano


  An opening in the Earth's crust where lava, molten rocks, and gaseous materials are forced out
• Volcanoes


  • Vary in different sizes - some are low-lying depressions, some are small, some are tall
• How a volcanic eruption occurs

  1. Tectonic plates collide

  2. Massive rocks underground deform

  3. Temperature and pressure build up

  4. Rocks melt to become magma

  5. Magma rises to the surface and volcanoes erupt
• Crater


  The opening of a volcano
• Magma chamber


  Deeply under the crater, where the magma is located
• Volcanic vent


  The cylindrical channel that connects the crater to the magma chamber
• Volcanic eruption


  When magma is released from the crater
• Lava


  The magma that flows out on the surface
• Secondary vent or siphon


  Another way out for the magma when a volcano erupts
• Types of volcanic eruptions

  • Explosive
  • Non-explosive
• Explosive eruption


  Large amounts of pyroclastic materials (lava, ash, volcanic gas, rocks) are ejected into the air
• Pyroclastic materials


  Lava, ash, volcanic gas, and rocks
• Non-explosive eruption


  Lava just flows out of the crater and gaps along the side of the volcano
• Types of volcanoes by activity

  • Active
  • Dormant
  • Extinct
• Active volcano


  Currently erupting or showing regular signs of activity like earthquakes and significant gas emission
• Dormant volcano


  Has erupted in the past but has entered a long period of inactivity
• Extinct volcano


  Has not shown signs of activity for a long period of time and has no records of volcanic eruptions in the past thousand years
• Volcanic eruptions


  Can cause damage to plants, animals, people, and properties
• Volcanic eruptions


  Can also have beneficial effects in nature and for people
• Negative effects of volcanic eruptions


  • Hot lava flow can burn anything in its path
  • Mud flow or lahar can cause landslides, flooding, and damage to buildings and farms
  • Volcanic ash and dust can irritate lungs and cause health problems
  • Strong eruptions can trigger earthquakes and damage buildings
• Positive effects of volcanic eruptions

  • Pyroclastic materials can make soil fertile for planting and farming
  • Geothermal steam from fumaroles can generate electricity
  • Produce industrial materials like pumice and sulfur
  • Rocks from volcanoes help scientists study the Earth's interior
• Crust


  The outer cool layer on which we live
• Crust


  • Covered with landforms, air and water
• Mantle


  The layer below the crust
• Mantle


  • Very hot
  • Consists of rocks in molten form
• Core


  The layer located just below the Mantle
• Core


  • Divided into two parts: outer core (in liquid state) and inner core (in solid state)
• Metals in the Core

  • Nickel
  • Iron
• Sometimes, hot melted rocks called lava come out to the surface of the earth. Such places are called volcanoes.
• Formation of Earth


  1. Very hot

  2. Rains and thunderstorms cooled the outer portion

  3. Different life forms started originating
• Layers of the Earth

  • Crust
  • Mantle
  • Inner Core
  • Outer Core
• Crust


  • Thin outer layer of the Earth where we live
  • 3-5 miles thick in the ocean floor
  • 25 miles thick on land
  • Made of solid rock and minerals
• Mantle


  • Thicker than the crust at almost 1900 miles deep
  • Makes up about 85% of the Earth's weight
  • Solid rock but not completely hard
  • Made of slightly different silicate rocks with more iron and magnesium
• Tectonic plates


  • Combination of the outer mantle and the crust
  • Move very slowly about a couple of inches per year
  • The place where the plates touch each other is known as the fault
• Tectonic plates move and the boundaries bump up against each other

  May cause an earthquake
• Outer Core


  • Made up of hot liquid iron and nickel
  • About 1400 miles thick
  • Creates a magnetic field and a protective barrier around the Earth
• Inner Core


  • Made up of solid iron and nickel
  • About 1500 miles thick
  • As hot as the sun's surface, around 9000-13000 degrees Fahrenheit
• Earthquakes are caused by the release of energy that generate waves which travel in all directions causing the shaking of earth's surface
• Tectonic plates


  Jigsaw puzzles of around 19 to 20 pieces that make up the earth
• Tectonic plates are placed on a hot partially molten layer of earth's mantle, which is the reason why these pieces are continuously moving