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Transcript of Volcanos
Extrusive rocks) Intrusive Rocks)
-How Volcanoes erupt
Everything you need to know about Volcanoes
By Alexandra Arrowsmith
The earth is made up of three layer parts. The outer crust is the layer on which we live. It is estimated to be about 1800 miles deep. Then there is the mantle and then the core (inner and outer core)
The mantle is made up of melted material and gases. Melted materials are solids (like rock) that have turned into liquid because of extreme heat. The name for melted rock and other gases in the earth’s mantle is Magma. Magma is liquid made up of many crystals, fragments and gases including oxygen, silicon, iron, aluminum, magnesium and manganese. When they cool off on the earth’s surface, they turn into magmatic or igneous rock.
Whenever extreme pressure builds in the mantle, along fault lines (openings or cracks in weak spots in the earth’s crust) an eruption is likely to happen next. During an eruption, melted materials (soon to become lava) gush out through spaces in the crust to the surface.
NOTE: Melted rock is called magma when it is inside the crust but once it gets to the surface of the earth it is called lava.
Eruptions can be in the form of lava fragments shooting into the atmosphere and forming thick clouds of lava. Some also flow slowly from the vent, flooding the area around it. Very fine particles of ash may also be discharged high into the stratosphere and further carried away by wind action.
Three main rocks
Igneous, metamorphic and sedimentary
Igneous rocks are formed from melted rock.
1) intrusive igneous rocks such as granite that solidify below the earth's surface.
2) extrusive igneous rocks such as basalt that solidify on or above the earth's surface.
A metamorphic rock is a result of a transformation of a pre existing rock. The original rock is subjected to very high heat and pressure, which causes obvious physical &/or chemical changes.
Foliated metamorphic rocks
Non Metamorphic rocks
Sedimentary rocks are types of rock that are formed by the deposition of material at the earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral &/or organic particles to settle and accumulate minerals to precipitate from a solution.
• Stay away from active volcanoes.
• If you live near an active volcano, keep goggles and a mask in an emergency kit, along with a flashlight and a working, battery-operated radio.
• Know your evacuation route. Keep gas in your car.
If a Volcano Erupts in Your Area-
• Evacuate only as recommended by authorities to stay clear of lava, mud flows, flying rocks and debris.
• Avoid river areas and low-lying regions.
• Before you leave the house, change into long-sleeved shirts and long pants and use goggles or eyeglasses, not contacts. Wear an emergency mask or hold a damp cloth over your face.
• If you are not evacuating, close windows and doors and block chimneys and other vents, to prevent ash from coming into the house.
• Be aware that ash may put excess weight on your roof and need to be swept away. Wear protection during cleanups.
• Ash can damage engines and metal parts, so avoid driving. If you must drive, stay below 35 miles (56 kilometers) an hour.
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 fallen around the vent (and which is the outside of the volcano)
Composite volcanoes are steep sided volcanoes composed of many layers of volcanic rocks, usually made from high viscosity lava, ash and rock debris. Mount Rainier and Mount st Helen are examples of this type of volcano.
Shield volcanoes are the largest volcanoes on Earth that actually look like volcanoes. Shield volcanoes are almost exclusively basalt, a type of lava that is very fluid when erupted. For this reason these volcanoes are not steep. Eruptions that shield volcanoes are only explosive if water somehow gets into the vent, otherwise they are characterized by low-explosive fountaining that forms cinder cones and spatter cones at the vent, however, 90% of the volcano is lava rather than pyroclastic material. Shield volcanoes are the result of high magma supply rates, the lava is hot and little-changed since the time it was generated.
Lava is the melted rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This melted rock is formed in the interior of some planets, including Earth, and some of their satellites.
Examine the properties of materials and substances (solids, liquids, gases) and identify what changes can occur
Identify the relationship between the parts of a system and explain how these systems operate for example- body systems
Follow a scientific process- questioning, predicting, conducting, analyzing or evaluating
Identify the structural features and adaptions that help living things survive in their environment