The objective of this project is that I am going to explain about , the different types of and tell some other interesting facts on this subject. Here is some background information about . are vents in the Earth where molten rock (magma) and gases erupt. Molten rock inside the Earth is called magma. The source of the magma-producing heat is thought to the decay of radioactive isotopes in the Earth. When magma flows out of the volcano it is called lava. Lava may erupt out of a volcano in many different forms, from large pebbles to dust. The ....