Magma and lava are the same substance in two different forms. Magma is molten rock that is found beneath the earth's crust, while lava is what magma becomes once it reaches the surface and erupts from a volcano or crack in the earth.Continue Reading
Magma can also contain many other components besides just molten rock, including gases and crystals. This mixture maintains a temperature between 1,600 and 2,400 degrees Fahrenheit. The molten rock often contains silicon, iron, carbon, aluminum, magnesium and different alkalis. Magma is heated by geothermal convection and pressure. Typically, it is found several kilometers beneath the earth's surface.
The composition of lava determines whether its flow is explosive, fast-moving or slow and highly viscous. Temperature plays a less significant role in the look and feel of the volcanic rock that forms once the lava cools down. Pumice is one igneous volcanic rock that is shaped by its composition and the type of eruption. As lava violently shoots into the atmosphere, it rapidly cools and decompresses, allowing air bubbles to permeate the rock, leaving a bubble-marked texture and a light weight. Obsidian, on the other hand, is a high-silica rock that forms from quick-cooling lava found on the ground in highly viscous flows.Learn more about Volcanoes
A volcanic neck forms when lava inside a caldera cools after magma stops feeding the mountain, and then the outside of the extinct volcano erodes after millions of years. The cooled lava remains intact because it is harder than the surrounding rock that eroded. Perhaps the most famous volcanic neck in the United States is Devil's Tower in Wyoming.Full Answer >
A volcano forms when magma pushes up through the Earth's crust from below, depositing lava on the surface. This lava cools, creating volcanic rock. Over time, repeated eruptions of lava build a cone-shaped mountainous structure, producing a volcano.Full Answer >
Volcanoes erupt to release pressure built up in the magma chamber by expelling the magma as lava. Along with lava, a volcanic eruption releases ash and greenhouse gases such as sulfur dioxide and carbon dioxide.Full Answer >
When a volcano erupts, magma from beneath the Earth is forced out of the volcano's mouth in the form of molten lava. Large amounts of gases and ash can also be released with the lava, depending on the type of eruption.Full Answer >