1. Lava

3. Is this lava or magma?
This Photo by Unknown Author is licensed under CC BY-SA

4. Answer: Lava Why?

5. Viscosity
means resistance to flow, the “gooeyness,” or how thick it is
high viscosity
high silica content
explosive eruptions
low viscosity
low silica content
gushing eruption
(**remember pumpkin lab**)

6. Viscosity Activity You have 4 liquids: Maple Syrup Water Vegetable Oil
Marinara Sauce
After having a race with the liquids on your paper plate…
put them in order from fastest to slowest
Which do you think has high viscosity?
Which do you think has low viscosity?

7. I want each group of 2 (elbow partners) to grab 1 plate with the 4 liquids
Tip the plate carefully so that it is diagonal and so that the liquids begin to flow down the plate
Record some observations you noticed.

8. On your paper, (using your own logic and observations) put the liquids in order from fastest to slowest.
What do you notice about the liquids? How did this relate to viscosity?
What made the fastest liquid fast? What made the slowest liquid the slowest? Why?

9. Types of Lava There are 4 main types of lava: A’a Pahoehoe Pillow
Blocky

10. A’a
a’a lava flows have a very rough, rubbly surface because of their high eruption rates
the upper surface of the lava cools and becomes rock, it is continually ripped apart by the moving molten lava inside the flow
pieces of the rocky surface are broken, rolled and tumbled along as the lava flow moves
when it cools to a solid, a’a lava flows look like a jagged heap of loose rock that is very difficult to walk over without stumbling and getting cut
high viscosity, cooler, & slow moving

12. Pahoehoe
pahoehoe lava flows have a relatively smooth surface texture because of their low eruption rates
it develops at surface crusts and form thick plates with ropy and/or gently rolling surfaces
low viscosity, hotter, & faster moving

14. Pillow Lava pillow lava forms from underwater eruptions
“pillow” lava is called this because it forms rounded lumps that look like fat pillows, or cushions of a sofa
the pillows can sometimes form piles as high as 10 meters
pillow lava flows can be hundreds of meters to kilometers long

16. Blocky Lava
it is cool stiff lava that does not travel far from the main erupting vent
it cools and forms sharp edged chunks

17. Pyroclastic Flow
high density flow consisting of a hot (up to 800 degrees celcius), poisonous mixture of gas and pyroclastic material (tiny volcanic rocks ejected into the air)
this moves downslope at a speed of up to 200 km/hr!

19. Volcanic Bombs
volcanic bombs are large pieces of magma that harden in the air as the erupt out of a volcano.
they can form in a variety of sizes and shapes.

21. volcanic ash forms when gases from stiff magma expand rapidly
the walls of the gas bubbles explode into tiny glasslike slivers (like the top pic)
ash makes up most of a pyroclastic eruption
Volcanic Ash