Welcome to Science 10/20

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Welcome to Science 10/20

• Todays Schedule
• 1. Question of the Day
• 2. Introduction to Volcanoes
• 3. Begin Ch. 9 Section 1 Notes/Discussion

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Question of the Day

• A pitcher on the Cleveland Indians baseball team
  exerts a pushing force on a baseball when
  delivering a pitch to a batter. The batter swings
  and misses.
• What applies a force that most likely causes the
  ball to stop its motion?
• A. air friction
• B. Earths gravity
• C. the catchers mitt
• D. the shortstops glove

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Volcano Types

• Shield, Cinder-Cone, and Composite.
• What causes these different types of volcanoes to
  form?
• The different ways in which they erupt and the
  different materials that are erupted.

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Volcanic Eruptions

• Right now 20 volcanoes are erupting around the
  world.
• There are nearly 1500 active volcanoes on Earth.
• The largest volcano is on the planet Mars. Its 27
  km high.
• About 900 people are killed by volcanoes each
  year.
• 500 Million people currently are at risk to be
  killed by volcanoes.
• "Mt. Saint Helens' Powerful Erruption"

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Why do volcanoes erupt?
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I. Kinds of Volcanic Eruptions

• Eruptions are classified as either quiet or
  explosive.
• How a volcano erupts depends on the gasses,
  silica, and viscosity of the magma.
• Silica-similar to sand, one of the key components
  of
• magma
• Viscosity- the resistance of a
• liquid to flow
  

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II. How the Eruption Works

• A volcanic eruption is similar to an exploding
  pop can.
• Gasses inside the volcano build up. As gas builds
  up, so does the pressure. When the pressure is
  too great, the volcano erupts.
• BBC NEWS Science/Nature Animated
  guide Volcanoes
• OUR RESTLESS PLANET

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III. Quiet Eruptions

• Magma has low silica, low viscosity, and low
  gasses so it flows easily.
• Hawaiian Islands were made this way.
• volcanic eruption

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Welcome to Science 10/21

• Have a seat with your lab group and put your name
  on your lab ticket.
• Todays Schedule
• 1. Science News
• 2. Review
• 3. Viscosity Lab

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IV. Explosive Eruptions

• Magma has high-silica and high viscosity, making
  it thick and sticky. High Gas.
• Magma does not flow.
• Builds up in the pipe like a cork in a bottle .
• Pressure builds up until the volcano explodes.
• Make a Volcano

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Mount St. Helens
Should I Stay or Should I Go? During Eruption
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Mount St. Helens
Before Eruption After
Eruption "Mt. Saint Helens' Powerful
Erruption"
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Mt. St. Helens 2003
Mt. St. Helens 1984
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V. Explosive Eruptions

• Explosive eruptions break lava into fragments
  that quickly cool into pieces of different sizes.
• Large pieces bombs
• Small pieces cinders
• Pyroclastic flow- mixture of hot gas, ash,
  cinders, and bombs
• -pyroclastic-flow-video.htm

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VI. Stages of Volcanic Activity

• Active, dormant, or extinct?
• Active- erupting or shows signs of erupting.
• Dormant- may awaken in the future.
• Extinct- unlikely to erupt again
• Is a volcano ever really extinct?
• No, at anytime a volcano thought to be extinct
  could reawaken.

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How It All Starts

• Magma from the mantle rises up through the crust
  because it is less dense.
• Magma becomes trapped beneath layers of rock.
• Weak spots in the crust allow trapped magma to
  reach the surface, forming a volcano.

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At the Surface

• Magma Chamber- pocket of magma beneath a volcano
• Pipe- long tube that connects the magma chamber
  to the surface
• Vent- opening where molten rock and gas leave the
  volcano

Pipe, Vent, Magma Chamber, Crater, Lava Flow
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At the Surface

• Lava flow- area covered by lava as it pours out
  of a vent.
• Crater- bowl shaped area that may form at the top
  of a volcano.

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Question of the Day

• Correctly the match the stages of volcanoes with
  the definitions.
• A. A volcano that is unlikely to erupt again.
• B. A volcano that is erupting or shows signs of
  erupting.
• C. A volcano that may awaken in the future

• Active
• Dormant
• Extinct

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Todays Objectives

• 1. Question of the Day
• 2. Open book quiz
• 3. Continue research on volcanoes