What is a Volcano?
The earth is made from 4 layers, the inner core, the outer core the mantle and the crust. The crust is broken into pieces called tectonic plates. When these tectonic plates rub together they create pressure, when the pressure builds up, the mantle pushes through the crust which forms a volcano. Rocks, ash and lava fragments come spitting out of the crater of volcanoes in an eruption. Lava can erupt out of a volcano in an explosion or it can gently drizzle out. There are 4 different shapes of volcanoes. There are Cinder cone volcanoes, Composite volcanoes, Shield volcanoes and Lava dome volcanoes.
Obsidian is an Igneous that is formed when molten lava is suddenly cooled when it flows into water. Obsidian is a naturally occurring volcanic glass formed as an outstanding igneous rock.
Facts: Obsidian can only form near active volcanoes
When obsidian breaks, the fractures are very sharp which is why it was used for tools
Pumice is a Igneous rock.The holes are vesicles that are actually gas bubbles trapped inside during rapid cooling in the molten magma. The materials cool so fast that the molecule cant get into a crystal form, so pumice is volcanic glass known as a mineral
Facts: Pumice is short for Pumicite
The size of pumice can range from tiny dust particles to pumice pieces the size of a house.
Rhyolite is a igneous rock formed
How It Is Formed: Formation of Rhyolite usually is in continental margin volcanic eruptions where the granitic magma reaches the surface.
Facts: Due to the release of Huge amounts of trapped gases, the eruptions of Rhyolite may be highly explosive.
What impact do volcanoes have on the world we live in?
Volcanoes are harmful because they can cause lots of destruction and damage to buildings, houses and the environment. Volcanoes can also let out ash and smoke when it's erupting which pollutes the air. The weathering of volcanic rock caused by rain and temperature changes can negatively affect our land and stone buildings by wearing them away for example the statue of queen Victoria in london was so badly weathered that the nose crumbled away and had to be replaced.
Volcanoes can help the earth because the ash has nutrients and minerals which help plants grow and also help soil on farms. Volcanoes are good for heating because they create a lot of energy which is taken from the earth through drilled holes or geysers and used in power plants. Rocks and minerals help us because for instance obsidian can be carved into a tool and used for cutting things. Pumice can be used for multiple purposes including sharpening tools and removing dry skin. They can also be used in the making of concrete and limestone. Minerals are mined and used to make everyday things for example match stick heads are made from sulphur, pencil leads contain graphite and baby powder is made from a mineral called talc.