Volcanoes:
Bringing us rock soup!
Volcanoes are sort-of like secret doors to the inside of the earth. The only problem is that the door only opens one way: out!
If we could travel into an active volcanic vent (opening) and stand the heat from the molten rock, we could learn alot more about the interior of the earth. Geological research now says that volcanic magma begins at the base of the crust and moves upward eventually erupting in a volcano. There are two substances that come out of volcanoes, one is lava which is molten rock. The other is a category called pyroclastics (volcanic bombs), which are particles of hot debris. Water and gases are also produced during an eruption.
There are three main kinds of volcanoes: shield volcanoes, stratovolcanoes and cinder cones. The Hawaiian Islands are an example of the action of shield volcanoes. Over thousands of years, shield volcanoes spread fluid lava over wide areas building up formations from the sea floor. Hawaii is the biggest formation of lava in the world.
Stratovolcanos are the most frequently found type of volcanoes. They are the most frightening kind of volcanoes because after they explode lava seals the opening and then the pressure builds up until the next time it explodes!
Cinder cone volcanoes are conical hills and can occur in all sizes rising sharply above the land.
Volcanoes erupt for short periods of time and then can be dormant (inactive) for long periods of time.