Lava

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

Answer: Lava Why?

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**)

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?

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.

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?

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

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

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

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

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

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!

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.

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