Embedded Files
Title: Volcano Land Formation
***DATA TABLE***
Principle(s) Investigated:
* This activity is a great culminating activity after studying about the earth's tectonic plates. It is also a great way to introduce students to the various layers the make up our planet.
* Lastly, students will investigate the effects volcanoes have on the environment.
6th Grade:
1. Plate tectonics accounts for important features of Earth's surface and major geological events. As a basis for understanding this concept:
b. Students know Earth is composed of several layers: a cold, brittle lithosphere; a hot, convecting mantle; and a dense metallic core.
f. Students know how to explain major features of California geology (including mountains, faults, volcanoes) in terms of plate tectonics.
Materials:
~ 2 spoons of sodium polyacrylate (found in baby diapers)
~ 1 cup of water
2 plastic cups
(1) spoon
(1) aluminum tray
a few books to create a slope
(1) Scale
(1) rulers
Procedure: Give a detailed explanation of the procedure and include diagrams if possible.
1) Have students fill two cups with 75ml of water each.
2) Place 1 drop of orange food coloring in one cup and 1 drop of red food coloring in the other cup. (this will help you better distinguish the two substances)
3) Add 1 gram of sodium polyacrylate in the yellow cup.
4) Add 0.25 grams of sodium polyacrylate in the red cup.
5) Place both globs on the sloped aluminum tray and release them at the same time.
6) Mark distance the two travel in 5 seconds.
Student prior knowledge:
Students will require some prior regarding the construct of earth.
In order for this demonstration to have a greater impact, students should already now how volcanoes are made.
Explanation:
The shape a volcano takes is greatly impacted by the type of lava from which it is created. This activity demonstrates how the viscosity of the lava is determined by the amount of silica found in it. The more silica there is in the lava, the more viscous the lava will be. High-silica volcanoes tend to be tall, with steep sides. On the other hand, low-silica volcanoes are more bowl shaped.
Questions & Answers:
What may have caused these two volcanoes to form so differently?
The type of lava the volcano is made out of.
Besides silica content, what else may determine the speed at which lava travels?
The terrain through which the lava is traveling may also affect lava's speed. Obstacles are also a factor (tree trunks, debris, retaining walls, river beds, etc.).
Would you rather live near a volcano with high silica lava or low silica lava? Why?
Volcanoes with ow silica lava tend to have less dramatic eruptions and are less of a threat to local communities.
Applications to Everyday Life:
This demonstration is a great way to explain the effects friction has on a moving object. An object with a high coefficient of friction will travel at a slower pace. Furthermore, this demonstration can also explain the effects slope has on the speed of an object. The steeper the slope, the faster the speed of the object. Finally, this demonstration can also be used as a way to determine speed. By obtaining the distance traveled over a particular number of seconds, students can calculate the speed of the lava and thus determine the speed of other moving objects.
Photographs:
Shield Volcano - low silica
Stratovolcano - high silica
Videos:
Build your own volcano!!!
http://dsc.discovery.com/convergence/pompeii/interactive/interactive.html
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