1. The Changing Earth: Chapter 3 Mountains and Volcanoes
3.2 (Part 1) Volcanoes form as molten rock erupts.

2. Volcano
Opening in Earth’s crust through which molten rock, rock fragments, and hot gases erupt

3. Parts of a Volcano
Magma Chamber – Magma that rises towards Earth’s surface collects in a magma chamber, Magma remains here until it either cools and forms igneous rock or erupts

4. Parts of a Volcano
Main Vent – The point on the surface where magma leaves the volcano
Side Vent – Magma is sometimes forced out through an opening on the side
Crater – Bowl shaped area that forms around the volcanoes vent

5. Parts of a Volcano Lava – Magma that has reached the surface
Lava Flow – River of lava that pours down the side of the volcano

7. Parts of a Volcano
Rock Fragments – A lot of the material erupted from a volcano comes as rock fragments of different sizes
Large fragments fall quickly but ash can be carried long distances by winds

8. Parts of a Volcano
Volcanic Ash (smallest – less than 2 mm in diameter) Ranges from the sizes of dust to the size of rice grains

9. Parts of a Volcano
Volcanic Cinders (Medium) Contain holes and tunnels left by escaping gases

10. Parts of a Volcano
Volcanic Bombs and Blocks (largest) Bombs are molten when they are thrown out and harden as they fly through the air, Blocks are solid pieces of rock and can be the size of houses

11. Parts of a Volcano
Volcanic Gases – Water Vapor and Carbon Dioxide, what looks like smoke rising from a volcano is actually ash and gases
Pyroclastic Flows – dense cloud of superhot gases and rock fragments that races downhill, up to 800 °C and 160 KM/Hr
Most dangerous type of volcanic eruption