Chapter 1 Lesson 1 Volcanoes Add Land Chapter

Chapter 1 - Lesson 1 Volcanoes Add Land Chapter 1 The World’s Geography

Volcanoes Add Land page 22 • Sometimes when two of Earth’s plates push against each other, the edge of one plate slides beneath the other. • As rock in the upper plate is pushed up, rock in the lower plate is pushed down into the Earth’s mantle. • Heat within the mantle causes rock in the lower plate to melt. This rock is called magma. Magma - is a mixture of molten or semi-molten rock, that is found beneath the surface of the Earth

Volcanoes Add land • When rock melts it produces gas • The gas mixes with the magma and slowly rises through cracks in the Earth’s surface. • Lava – the name of the magma that has escaped onto the Earth’s surface • Lava may escape slowly or other times it erupts violently

Volcanoes Add Land

Volcanoes Add Land • There are different types of volcanoes based on what type of lava comes out of it • Conical (cone-shaped) Volcanoes are formed through violent eruptions spewing the lava high in the air. • These are also called cindercone volcanoes

Volcanoes Add Land • Shield Volcanoes are formed from slow moving lava spreading across the land

Volcanoes Add Land • Volcanoes are also classified by how often they erupt • Active volcanoes – have been erupting or erupted ever since people have been keeping track of them. • Dormant volcanoes – have become inactive but not long enough for us to know if it will erupt again. • Extinct or Dead volcanoes – have no record of activity and will probably never erupt again.

Volcanoes Add Land • Active Mt. Kilauea, Hawaii • Dormant – Mt. Rainier, Washington Extinct - Mount Kilimanjaro Mountain in Tanzania

• What are the different types of volcanoes? What makes them different?

Terms to Know • Lava • Magma • How are volcanoes formed?