Volcanoes – Part 1

For the last three months, “volcanology” has been on the minds of Upper Elementary students and their teachers. The foundation of their volcano studies began with an understanding of plate tectonics. On Earth, there are seven or eight major plates (depending on how they are defined)and many minor plates. Our students investigated 16 different plates. Where plates meet, their relative motion determines the type of boundary: convergent (move towards each other), divergent (move away from each other). Earthquakes and volcanic activity occur along these plate boundaries.

Three different kinds of volcanoes dominate the landscape. Stratovolcanoes are tall and explosive, think Mt. Fuji. Cinder cone volcanoes are not as tall as stratovolcanoes, but are still explosive, such as Mt. St. Helens. Finally, the third variation is call the shield volcano, which is flat and not explosive, but is always putting out steam and oozing magma, like Kilauea on the Big Island of Hawaii.

Once the students had the big picture of why certain volcanoes form in different parts of the Earth, depending upon the plate tectonics, they began to investigate the parts of the volcano (introduced to Montessori primary age students) and started to see why the magma chamber in a stratovolcano looked so different from the magma chamber of a shield volcano. The pressure in a stratovolcano keeps building up, until there is too much force and it explodes violently.

Viscosity is another important feature of volcanic studies. It is the measurement of “the extent to which a fluid resists a tendency to flow.” Some volcanoes have high viscosity such as a shield volcano, where the magma can be observed (relatively safely) as it is oozing slowly out of the main crater of the volcano, cooling and building land as it hardens. In class, the students learned about the concept of viscosity by running a side experiment where they timed the movement of molasses, versus oil, to see which one took more time to reach the end of the board (molasses has higher viscosity).

*Join us on Wednesday as we conclude our two part series on volcanoes.