I. Volcanoes are found all over the world, especially along Earth’s plate boundaries
a. Pressure builds up inside the earth causing hot molten rock from Earth’s mantle to push through the surface.
b. Dried lava forms igneous rocks like pumice and basalt.
c. Example: Mount Pinatubo erupted in 1991 and so much volcanic ash was exploded into the air that the temperature of the whole Earth dropped by 1 degree Celsius for a few months
d. Dormant volcanoes have not erupted for a long time.
e. Active volcanoes have erupted recently.
II. There are all different types of volcanoes
a. Cinder cone volcanoes—formed when ashes and cinders are blown out of a single vent, quickly forming a small cone-shaped mountain
b. Composite/stratovolcanoes—formed at convergent plate boundaries, where one plate is pushed under the other. The plate melts into magma which is forced through the surface through multiple cracks or vents. The lava is viscous—thick and slow moving.
c. Shield volcanoes—often form underwater at divergent plate boundaries or over “hot spots.” The lava is runny and made of basalt.
Mrs. Ana Rhyne
I teach 4th grade math and science at Weatherstone Elementary School. I graduated from Meredith College with a BA in Spanish and K-6 licensure.