1. Volcanoes Liquid Hot Magma. Tungerahua Volcano, Ecuador
Talk about this volcano when it erupted and what it is doing right now.
Tungerahua Volcano, Ecuador
Picture by Alcinoe Calahorrano
Liquid Hot Magma.

2. Volcano Stats Definition of Volcano Number of active volcanos = ?
Mountain that forms when molten rock (magma) is forced to the Earth’s surface
Number of active volcanos = ?
20 erupting right now (50-60/year) (160/decade)
Number of volcanologists = 1,500
MASS, DENSITY, AND ESCAPE VELOCITY The Earth's mass is about 5.98 x 1024 kg. The Earth has an average density of 5520 kg/m3 (water has a density of 1027 kg/m3). Earth is the densest planet in our Solar System. To escape the Earth's gravitational pull, an object must reach a velocity of 24,840 miles per hour (11,180 m/sec).

3. Nonexplosive Eruptions
Volcanic Eruptions
Lava flow
Lava fountain
Nonexplosive Eruptions
Explosive Eruptions
What is Lava?
-magma that flows onto the Earth’s surface

4. Volcano Model
Demonstration

5. Write/draw this in your science journal.
1. What did you learn?
Write/draw this in your science journal.
Vents
Volcanoes form around vents that release magma onto the Earth’s surface.
Lava
Magma chamber

6. The Composition of Magma Determines whether it is explosive or not!
High water content
More likely to be !!!
High content
More likely to be !!!
Why?
Silica has a thick, stiff consistency
Flows slowly
Tends to Harden in the volcano’s vent
EXPLOSIVE
silica
EXPLOSIVE
The Earth is made of many different and distinct layers. The deeper layers are composed of heavier materials; they are hotter, denser and under much greater pressure than the outer layers. Core: The Earth has a iron-nickel core that is about 2,100 miles in radius. The inner core may have a temperature up to about 13,000°F (7,200°C = 7,500 K), which is hotter than the surface of the Sun. The inner core (which has a radius of about 750 miles (1,228 km) is solid. The outer core is in a liquid state and is about 1,400 miles (2,260 km) thick.

7. Explosive Volcano Model
Demonstration

8. Write/draw this in your science journal.
2. What did you learn?
Write/draw this in your science journal.
a. What physical event causes explosive eruptions?
b. Would high water content increase the likelihood of having an explosive eruption?
c. Would high silica content increase the likelihood of having an explosive eruption?

9. What Erupts from a Volcano?
Blocky lava
Lava can be
thick or thin.
Pahoehoe Aa
Pillow lava

10. Lava Flow
Activity

11. Loosen the gelatin volcano from the cups by dipping the cups briefly in the bowl of hot water.
Lay the pegboard on top of a food serving tray to collect drips.
Weave the airline tubing into the pegboard from the top and back up through the bottom so that 2” or so of tubing is sticking up out of the pegboard. Remove the plunger.
Fill the syringe with your prepared “magma.” Remove any air bubbles from the syringe and tubing by holding the syringe upright and squirting out a small amount of the liquid. Air tends to fracture the gelatin.
Unmold the gelatin by tipping the bowl over onto the center of the pegboard on top of the tubing and lifting the bowl. Do this VERY CAREFULLY so that the gelatin cast won’t develop cracks; a few small cracks are acceptable. The gelatin cast will spread and settle. It should resemble a colorless to milky volcano.
Inject the red water VERY SLOWLY, at a rate of about 20 ml/min. Each student should inject about 10mL into the volcano with the other students watching carefully.
What do you observe?
Use a plastic knife to slice open the volcano, and view the cross-section.

12. Write/draw this in your science journal.
3. What did you learn?
Write/draw this in your science journal.
a. Where did the lava flow in your model?
b. Did the lava choose the path of least resistance (weakest places), like cracks?
c. Did the lava deepen the existing cracks or make new cracks?

13. What Erupts from a Volcano?
Pyroclastic material
Rock fragments created by eruptions
magma explodes from volcano and solidifies in the air
existing rock is shattered by powerful eruptions
EXPLOSIVE
Lapilli
Volcanic bombs
Volcanic blocks
Volcanic ash

14. How do volcanoes affect the Earth?
Flows and Fallouts
hot ash can flow really quickly
Knock down buildings
Dam rivers (flooding/drought)
Kill crops and livestock
Climatic Changes
Ash & Gases can block sunlight
Drop average global temperature noticeably

15. Types of Volcanoes Shield volcano Cinder cone volcano
Composite volcano

16. Craters, Calderas, and Lava Plateau
From explosions of material out of the vent and the collapse of material back into vent
Caldera
Much larger depression that forms when magma chamber empties and its roof collapses
Lava Plateau
Forms when lava erupts from long cracks, or fissures, and spreads out evenly (thousands of km)

17. What causes volcanoes? The Formation of Magma
Mantle rock melts when the temperature increases
or the pressure decreases.
There are lots of uncertainties about why volcanoes form, because scientists have to rely on models based on rock samples and other data.

18. What causes volcanoes? Where Volcanoes Form
Tectonic Plate Boundaries!!!
There are lots of uncertainties about why volcanoes form, because scientists have to rely on models based on rock samples and other data.
~75% world’s active volcanoes in Ring of Fire

19. What causes volcanoes?

20. What causes volcanoes?
Hot Spots

21. How do volcanologists predict eruptions?
Measuring Small Quakes
Before eruption, increase in number & intensity
Measuring Slope
Bulges may form with magma (tiltmeter)
Measuring Volcanic Gases
Outflow of volcanic gases
Sulfur dioxide, carbon dioxide
Measuring Temperature from Orbit
Measure changes in temperature over time

22. You should not be a Volcanologist if….
You don’t like hiking, backbacking, rockclimbing, etc.
You are not interested in experiencing extreme temperatures and heights.
If you don’t like to travel to incredible places and see breathtaking views of the world.
Robert McGimsey
USGS
A. Ozerov

23. Eruption
Anticipation
Activity

24. Place 10mL of baking soda in center of a sheet of bathroom tissue
Place 10mL of baking soda in center of a sheet of bathroom tissue. Fold the corners over the baking soda and crease the edges so that they stay in place. Place the tissue packet in the middle of a large disposable pan.
Put modeling clay around the top edge of a funnel. Turn the funnel upside down over the tissue packet. Press down to make a tight seal.
Put safety goggles on and add 50mL of vinegar and several drops of liquid dish soap to a 200mL beaker, and stir.
Predict how much time will elapse before your volcano erupts. WRITE THIS DOWN!
Pour the liquid into the upturned funnel. Using a stopwatch, record the time you began to pour and the time your volcano erupts.
How close was your prediction?

25. Write/draw this in your science journal.
4. What did you learn?
Write/draw this in your science journal.
a. Was your time prediction close to the real time of eruption?
b. Are the eruption times similar for every group? If not, give at least one reason why this might be.
c. How is our experiment different from predicting the eruption of a real volcano?