Volcanoes
- A volcano is an opening in the earth's crust. It is like a "vent" through which lava can erupt.
- Volcanoes are formed as many layers of ash and cooled-lava build up over time.
- A volcano is also known as a hollow mountain.
- Some are active and some are dormant.
- Volcanoes can be found on land or on the ocean floor.
- 80% of volcanic eruptions happen under the oceans.