Why do certain types of volcanoes have different types of eruptions? Objective Students will learn about four types of volcanoes: lava dome, shield volcano, conical composite (stratovolcano), and cinder cone volcanoes. Each of these volcanoes has different types of eruptions based on magmatic composition and gas content. A simple lava lamp activity is used to illustrate how gases move through liquids, by discussing concepts such as density and viscosity. Background Volcanoes are openings called vents that allow for lava, rock fragments or debris, and steam to escape onto the earth's surface. M Duration: 30 Minutes.