1. Welcome to Science 10/20 Today’s Schedule 1. Question of the Day
2. Introduction to Volcanoes
3. Begin Ch. 9 Section 1 Notes/Discussion

2. 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. Earth’s gravity
C. the catcher’s mitt
D. the shortstop’s glove

3. 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.

4. 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"

5. Why do volcanoes erupt?

6. 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

7. 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

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

9. Welcome to Science 10/21
Have a seat with your lab group and put your name on your lab ticket.
Today’s Schedule
1. Science News
2. Review
3. Viscosity Lab

10. 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

11. Should I Stay or Should I Go?
Mount St. Helens
Should I Stay or Should I Go?
During Eruption

12. Mount St. Helens Before Eruption After Eruption
"Mt. Saint Helens' Powerful Erruption"

13. Mt. St. Helens 2003
Mt. St. Helens 1984

14. 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

15. 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.

16. 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.

17. 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

18. 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.

19. 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

20. Today’s Objectives 1. Question of the Day 2. Open book quiz
3. Continue research on volcanoes