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Eruptions!. What comes out of volcanoes? . Lava Rock fragments Ash Blocks. How does an eruption happen?. Magma is made of silicon and oxygen. Magma is also made up of gases. 1.) Gases in the magma begin to expand 2.) Gases have no where to escape 3.) Pressure builds up
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What comes out of volcanoes? • Lava • Rock fragments • Ash • Blocks
How does an eruption happen? • Magma is made of silicon and oxygen. • Magma is also made up of gases. 1.) Gases in the magma begin to expand 2.) Gases have no where to escape 3.) Pressure builds up 4.) Gases blow up and out of the volcano
Lava • Lava is magma that reaches Earth’s surface. • As magma makes its way up the volcano, it gets trapped in magma chambers. • When a chamber can no longer hold the magma, the chamber blows up, magma escapes, reaches Earth’s surface, and is then lava.
Ash • Pieces of volcanic rock fragments that are smaller than 2mm in diameter • Get carried long distances by the wind
Blocks • Large heavy pieces of volcanic rock • Some as big as houses • They are shot out and fall quickly back to Earth
Pyroclastic flow • A cloud of superhot gases and rock fragments • These flows race downhill • They reach temperatures of 1500 degrees Fahrenheit • Travel at 100 mph • Most dangerous part of an eruption
Scientists Monitor Volcanoes • Many volcanoes can lay dormant for years, and then once again erupt. • Before eruptions, there are some warning signs: • Small earthquakes • Steam coming from the volcano • Changes to the ground • Streams around the volcano get warmer