Volcanoes are geological formations where molten rock, ash, and gases from beneath the Earth's crust are expelled through openings in the surface, often forming mountains over time. Articles are a unique way for readers to learn about the world around them. In addition to building reading comprehension skills and increasing vocabulary, articles can be used for writing and research. Volcanoes is broken into 6 single-page sections: What are Volcanoes?, How Volcanoes are Formed, Parts of a Volcano, Types of Volcanoes, Staying Safe, Words to Know.