A Volcano is a gap in the earth where molten rock and other materials come to the earth's surface. Some volcanoes are just cracks in the earth's crusts. Others are weak places in the earth's crust, which occur on places where magma bubbles up through the crust and comes to the earth's surface. Magma is molten rock that occurs by partial melting of the crust and the mantle by high temperatures deep down in the ground. Once magma comes to the earth's surface it is called lava.
Composite or Strato-Volcano: built up of alternating lava and ash /rock particles. Andesitic magma can be both explosive and gentle. The more gentle eruptions form the lava layers and the more explosive eruption form the ash/rock layers
Ash: (volcanic): Fragments less than 2 millimeters in diameter of lava or rock blasted into the air by volcanic explosions. The MOST Dangerous eruptive material! Ash can travel for hundred of miles, it can block out the sunlight and change climate, it is poisonous to breath
Pumice: A light-colored, frothy, vesicular volcanic rock, usually of intermediate and felsic composition, formed by the expansion of gas in erupting lava. Commonly perceived as lumps or fragments of pea size and larger but can also occur abundantly as ash-size particles. Because of its numerous gas bubbles, pumice commonly floats on water
Pyroclastic Flow : Pyroclastic flows are fluidized masses of rock fragments and gases that move rapidly in response to gravity. Pyroclastic flows can be very hot. They can reach 1075 degrees Fahrenheit. They also move extremely fast, over 60 miles per hour.