Warm-up•What are some things that one must

worry about if a volcano erupts?

Chapter 3 Section 1: Volcanoes9/28/2011

Learning Targets•Students will understand the

characteristics of volcanoes.•Students will understand the dangers of

volcanoes.•Students will begin to gain an

understanding of the main locations of volcanoes.

Volcanoes•Volcano- a mountain built from magma (melted

rock) that rises to the Earth’s surface•Volcanoes may occur on land or under the sea.•If they occur under the sea, they may

eventually break the ocean surface.

•One minute quick write:▫What volcanoes do you know that have come

from under the sea and why do you think they came from under the sea?

Local Effects of Volcanoes•A volcano erupts when the pressure on its

inside becomes too great.•The land can not hold the pressure back,

and BOOOOOOOOOOOOOOOOOM! Mount Saint Helens!!!

•Some volcanoes have lava flowing out of them all the time, so no pressure builds up and they do not erupt. HAWAII!!!

•One Minute Quick Write:▫Why might some volcanoes be violent while

others are not?

Local Effects of Volcanoes•PYROCLASTIC FLOWS, or clouds of hot

dust, ash, and gases can flow down hills destroying and incinerating everything in its path.

•Volcanic ash can mix with melted water, producing MUDSLIDES.

•Ash falling to the ground can make roof buildings collapse, cause black outs, and seriously harm animals airways. (Yes, even humans.)

Global Effects of Volcanoes•Major volcanic eruptions can cause

climate change for several years.•Large eruptions cause volcanic ash and

sulfur gases to reach the upper atmosphere.

•The sulfur and ash spreads around the globe.

•They reduce the amount of sunlight reaching the Earth.

•This can cause a drop in average global surface temperature.

•Mount Pinatubo eruption 1991.

One minute quick-write:•After witnessing how the sulfur from

volcanic eruptions can decrease Earth’s temperatures, some scientists have suggested putting a lot of sulfur in the Earth’s atmosphere to counteract Global Warming.

•How do you think this is a good idea or bad idea?

YouTube Volcano Awesomeness!• http://www.youtube.com/watch?v=CgpNqrR318

U&feature=relmfu• http://www.youtube.com/watch?v=vBJ9xZws7ro