Welcome to Science 10/20

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. 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 Pipe, Vent, Magma Chamber, Crater, Lava Flow • 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

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. 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 Question of the Day

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