See the list on page 181 of your Webelos Scout book for help. Volcanoes are simply a place where there is an outlet for molten rock, called magma, to reach the surface of the ground. When the magma pours out, it is called lava. Geologists love to look at and study volcanoes. They are one of several types of mountains.
Volcanoes come in a variety of sizes and types.
One type is like those of the Hawaiian Islands. They rise from the floor of the sea and emerge from the ocean to form the islands. It takes millions of years of lava flows to build up a volcanic mountain by flow after flow cooling and becoming solid rock. Each layer hardens into rock and helps build the mountain. This type of volcano is called a shield volcano.