Volcanoes Meghan Knoth Tatum Printy Samantha Di Iorio
- Slides: 11
Volcanoes Meghan Knoth, Tatum Printy, Samantha Di. Iorio
What is a Volcano? �A mountain that opens downward to a pool of molten rock below earth’s surface. � Gases and rock shoot up through an opening and spill over with fragments of lava. � Some eruptions were strong enough to knock down whole forests.
Why do Volcanoes Erupt? � Earth’s crust is made of plates that fit together like a puzzle. � These plates sometimes move; the friction of the plates movement is what causes the eruption of the volcano this is called theory of plate tectonics.
Plate Tectonics Theory � When continents drift from place to place breaking apart, colliding, and grinding against one another. � All plates are moving in different directions and different speeds.
How many Volcanoes are there? � There are over 1, 500 active volcanoes in the world. � About 80 of these volcanoes are under water, such as oceans and large bodies of water.
Different Types of Volcanoes � Cinder cones – are circular or oval cones made up of small fragments of lava from a single vent that have been blown into the air, cooled, and then fallen around the vent.
Composite Volcanoes � Steep-sided volcanoes composed of many layers of volcanic rocks, usually composed of lava, rock, and ash � Examples: Mt. Saint Helens and Mt. Rainier
Shield Volcanoes � Shaped like a bowl or shield in the middle with long slopes made by lava flows. � Lava flows from these volcanoes are called flood basalts.
The World’s Largest Volcano � World’s largest, active volcano is Mauna Loa in Hawaii. � There is famous coffee grown here. � This volcano is 13, 677 feet above sea level; from its base to its summit, it is taller than Mt. Everest.
Difference between lava and magma: � Magma is liquid rock inside a volcano. � Lava is a liquid rock (magma) that flows out of a volcano. � Fresh lava grows red hot to white hot as it flows.
Why Lava takes a long time to cool: � Lava cools slowly because lava is a poor conductor of heat. � Lava flows slowly down and thickens as it hardens.
