Margaret Morgan: My name is Margaret Morgan, I am a science educator from Mad Science, I work in Pinellas County, Florida and now I am going to talk about volcanoes. A volcano erupts when magma or molten lava which is under a great amount of pressure finds a fissure or an opening in the Earth's surface and shoots out, usually along with certain amount of gas and ash. Volcanic eruptions have shaped our earth surface by resulting in the formation of mountains and islands and other geological formation. You are going to have volcanic activity in places where you have hot spots for a seismic activity.
Specifically in places where tectonic plates are being pushed together or pulled apart or where you have one being sucked under another. So one specific example of that will be the Pacific Rim of Fire which is specifically around the rim of the Pacific Ocean, you have a lot of seismic activity and as a result, a lot of volcanoes. The most common kind of volcanic formation is the Cinder Cone. Cinder Cone volcanoes often only erupt once and they form a small hill or mountain about 30 to 400 meters high. An example of the cinder cone is Sunset Crater in Arizona. Another common kind of volcanic formation is the stratovolcanoes, it is characterized by multiple eruptions and viscous lava that hardens before it flows very far. They usually result in tall mountains with the steep slopes and one example is Mount St. Helens. A Shield volcano is a volcano with shallow sloping slides formed by low viscosity lava. Low viscosity lava is going to be able to flow a long way before it hardens and that's how you get a shallow sloping volcano, one example of a shield volcano is Mount Kilauea in Hawaii. Alright let's conclude our discussion of volcanoes and now we are going to build our own volcano.