Volcanoes
volcanoes can be found all over the world, but many more are on the ocean floor. Volcanoes are like "portals into the heart of the earth." They are fueled by an ancient rat and have bottomless cauldrons that are bubbling and boiling thousands of miles below the surface. Most volcanoes, on land or underwater, are found where tectonic plates meet. In fact, about 75% of the world's volcanoes are on the "ring of fire," a path that follows the edges of several tectonic plates around the Pacific Ocean. Volcanoes can be divided into different types based on their size and shape. Stratovolcanoes, which look like tall, steep mountains, shield volcanoes, which are lower and have dome-shaped calderas, and mid-ocean ridges, which are underwater chains of volcanic mountains, are the main types of volcanoes. No matter how big or small a volcano is, it always sends out gas and molten rock. The journey of these emissions starts deep underground in the Earth's core, which can burn as hot as the surface of the Sun. The core sends its heat to the surrounding rocky mantle, melting some of the rock. The melted rock, called magma, is lighter than the surrounding solid rock layer, so it rises through the mantle and escapes through vents in the Earth's crust, causing volcanic eruptions.