To understand sound, you first need to understand matter. Everything is made up of matter. Learn more in the simulation above.
Interactive
Grades
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
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.