A volcano could be called a sleeping mountain--that is, until it wakes up! What is it like to witness the eruption of one of nature's majestic time bombs? Young readers can learn what makes volcanoes "tick," and read about some of the most famous eruptions in history in this SCIENCE READER. Step 4 Readers use challenging vocabulary and short paragraphs to tell exciting stories. For newly independent readers who read simple sentences with confidence.