Launch Interactive Share to Google Classroom The Earth is surrounded by a thin envelope of gases called the atmosphere. More than 500 active volcanoes erupt around the world affecting the Earth's atmosphere and global climate. Grades: 3 4 5 6 7 8 9 10 11 12 Subjects: ScienceEarth ScienceComposition of EarthWeather & Climate Collection: InteractivesActivitiesSimulations Series: NASA OnlineNASA Science Simulations