1. 8th grade Physical Science
Volcanoes
8th grade Physical Science

2. How are Volcanoes Formed?
Gases force magma, melted rock in the Earth to rise. If magma breaks through the Earth’s surface, a volcano is formed.

3. Three Different Types of Volcanoes
Shield Volcano
Composite Cone Volcano
Cinder Cone Volcano

4. Shield Volcano
They release relatively fast-moving less gassy lava, and tend to have less explosive eruptions than other types of volcanoes.
People often walk fairly close to these erupting volcanoes.
They usually form large, broad volcanoes.

5. Mount Bachelor in Oregon

6. Composite Cone Volcano
These volcanoes have explosive eruptions as a result of more gassy magma.
They are formed from layers of lava and ash.
Composite Cones are also known as stratovolcanoes.

7. Mount St. Helens in Washington

8. Cinder Cone Volcano These are the smallest and most common volcanoes
They are formed from explosive eruptions that shoot small pieces of magma and ash into the air.
The magma then cools and hardens as it falls back to the Earth, forming a cinder cone.
In many cases, cinder cones form on the sides of a larger volcano.

9. Mt. Etna in Italy

10. Active Volcano
Active volcanoes is one that has erupted since the last ice age approximately in the past 10,000 years.

11. Dormant Volcano
Dormant volcanoes would then be one that hasn’t erupted in the past 10,000 years, but it is expected to erupt again.

12. Extinct Volcano
Extinct Volcanoes would be one that nobody expects to ever erupt again.

13. Two Types of Eruptions
More gassy eruptions
Less gassy eruptions

14. More Gassy Eruptions
Explosive and violent eruption and magma shoots out of the volcano.

15. Less Gassy Eruptions
More quiet eruption. The magma just flows smoothly out of the volcano.

16. Ring of Fire
Many volcanic eruptions have occurred worldwide.