Please go to http://kids.discovery.com/games/build-play/volcano-explorer. Click
ID: 287088 • Letter: P
Question
Please go to http://kids.discovery.com/games/build-play/volcano-explorer. Click on “Enter” and then click on “Build your own volcano and watch it erupt.” Describe the type of volcano and eruption under the following scenarios.
A- High viscosity and low gas
B- Medium viscosity and low gas
C- Highest viscosity and high gas
D- 3/4 viscosity and high gas
E- Low viscosity and low gas
F- Low viscosity and high gas
How are A and B similar and different? Why?
How are C and D similar and different? Why?
How are E and F similar and different? Why?
Explanation / Answer
Volcanic eruptions are caused when magma (which is a mixture of liquid rock, crystals, and dissolved gas) ae expelled onto the Earth's surface. With increasing depth inside the Earth, all magmas contain gas dissolved in the liquid, but this gas stay by forming a separate vapor phase with decreasing pressure as the magma rises towards the surface of the Earth. The explosivity of a volcanic eruption mainly depends on its Viscosity and gas content.
Viscosity is the resistance to flow and the viscosity of a magma depends mainly on the amount of Silica it contains. and it increases with increasing content of silica.
Gases on the other hand are responsible for the explosive nature of a volcano because the volume of a gas expands as the pressure is decreased.
In the first case where A and B are involved, both contains low gas so both the eruptions will be less explosive whereas the difference between them will be that the lava from B (due to its medium viscosity) wil flow to a greater distance than that from A forming pahoehoe flows.
In the second case where C and D are involved, the similarity lies in their explosive character. Both of them will have highly explosive eruption due to their high gas content. On the other hand, C will flow to smaller distance than D owing to its higher viscosity which prevents its flow.
In the last case involving E and F, (both having low viscosity) will flow to greater distances forming lava flows or shield volcanoes whereas the difference between them will lie in the fact that F will erupt more explosively than E owing to its higher gas content which will expand drastically as the pressure decreases during the ascent of magma.