PRESENTATION OUTLINE
HOW ARE VOLCANOES FORMED ❓❔
When rock from the mantle melts, moves to the surface through the crust, and releases pent-up gases, volcanoes erupt. Extremely high temperature and pressure cause the rock to melt and become liquid rock or magma. When a large body of magma has formed, it rises thorugh the denser rock layers toward Earth's surface.
WHY DO VOLCANOES ERPUT Volcanoes erupt because of density and pressure. The lower density of the magma relative to the surrounding rocks causes it to rise (like air bubbles in syrup). It will rise to the surface or to a depth that is determined by the density of the magma and the weight of the rocks above it.
WHY DO WE HAVE VOLCANOES
Volcanoes are just a natural way that the Earth and other planets have of cooling off and releasing internal heat and pressure.
Volcanoes erupt because of density and pressure. The lower density of the magma relative to the surrounding rocks causes it to rise (like air bubbles in syrup). It is will rise to the surface or to a depth that is determined by the density of the magma and the weight of the rocks above it. As the magma rises, bubbles start to form from the gas dissolved in the magma. The gas bubbles exert tremendous pressure. This pressure helps to bring the magma to the surface and forces it in the air, sometimes to great heights.
HOW HOT IS LAVA
When lava first breaks through the surface of the Earth, it is an extremely hot liquid. On average, fresh lava can be between 1,300° F and 2,200° F! Depending on its exact temperature, fresh lava usually glows either orange/red (cooler) or white (hotter). -
