As part of our 4th grade curriculum, our social studies classes are learning about volcanoes. We wanted to know what makes a volcano erupt and if they are all found in the same places and if they are all the same.

We learned that volcanoes are divided into groups according to the way they act each time they erupt and according to their shapes. Earth is made up of three layers, the crust, upper mantle and core. The crust is the outermost layer of rock. It is thin and made of giant plates which float on the upper mantle. The upper mantle is hot, molten rock, which is always moving. It is the pressure in the mantle that forces magma to the surface. The core is the central part of the earth, which is made up mainly of iron. It has an inner core which is solid and an outer core which is liquid and very hot. Volcanic eruptions occur where the magma finds a way through cracks in the earth's crust, usually at the edges of plates.

Through our research we found that there are three main types of volcanoes. They are Composite Volcanoes, Cinder Cone Volcanoes and Shield Volcanoes.