Skip Navigation

  Button that takes you to the modules and activities page. Button that takes you to the teacher pages. Button that takes you back to the home page. Button that takes you to the Problem Based Learning model. Button that takes you to the references page.Imape map of some Volcanoes puzzle pieces.  Please have someone assist you with this.

Button that takes you to the Types of Volcanoes page.
Button that takes you to the Types of Lava: page 2. Button that takes you to the Types of Lava: page 1. Image that says Types of Lava: page 3.
Button that takes you to the Sizes of Eruptions page.
Button that takes you to the Volcanic Eruption Animations page.

 

 

 

 

 

 

 

Image demonstrating what happens when there is high water and low silica.  Please have someone assist you with this.Types of Lava
Different types of lavas show behaviors that are similar to our analogies of blowing bubbles in water or a milk shake. If an erupting lava has low viscosity ( like water) and little or no dissolved gases, it simply flows out of the central vent and spreads far and wide over the surface (see low water/low silica figure). If it has high viscosity (like a milk shake) and no dissolved gases, the lava oozes slowly out to form a bulbous dome which hardly moves at all (see low water/high silica figure). In either case, you could stand nearby in relative safety. If the erupting lava has lots of dissolved gases, the gases come out of solution and form bubbles as the lava approaches the surface. If the viscosity of the lava is low, the lava bubbles and froths a great deal right at the surface, tossing out tiny cinders and larger "bombs" of lava that quickly cool and fall back to the ground. This type of eruption (see high water/low silica figure) produces a spectacular "fire fountain" directly over the vent, usually resulting in a cinder cone. Any remaining lava quietly flows away.
Image demonstrating what happens when there is high water and high silica.  Please have someone assist you with this.However, the last combination, lots of dissolved gases and high viscosity, is deadly (see high water/high silica figure). As the lava oozes to the surface, the gases quickly form bubbles that turn the lava into a red-hot froth that explodes out of the ground as a searing, grayish cloud of superheated steam and tiny particles called ash. The ash forms when the walls of the gas bubbles burst into tiny fragments. This type of lava causes explosive eruptions at volcanoes like Vesuvius and Mount St. Helens.

[ Types of Volcanoes ] [ Types of Lava: page 1 / page 2 / page 3 ]
[
Sizes of Eruptions ] [ Volcano Eruption Animations ]
[ References ] [ PBL Model ]

[ Home ] [ Teacher Pages ] [ Modules & Activities

Button that takes you back to Volcanoes main page.


HTML code by Chris Kreger
Maintained by ETE Team
Last updated November 10, 2004

Some images 2004 www.clipart.com

Privacy Statement and Copyright 1997-2004 by Wheeling Jesuit University/NASA-supported Classroom of the Future. All rights reserved.

Center for Educational Technologies, Circuit Board/Apple graphic logo, and COTF Classroom of the Future logo are registered trademarks of Wheeling Jesuit University.