Transcript Slide 1
` Hi, My name is Noah. How would you like to go on an adventure with me? Great!! I am going to show you what volcanoes are and how they work. Ready? Lets go!! Well, here we are. You may be thinking, “where are we?” We are at the base of a volcano. A volcano looks like a mountain, but has many differences. A volcano is a landform, (like a mountain) where magma erupts through the earths crust. You can think of a volcano like a pressure valve, that releases its pressure that has built up inside the earth. Before we can fully understand volcanoes, we need to understand what is inside them. Inside a volcano is molten rock or magma, which is basically melted rock. It is also extremely hot. Magma can be up to 3,000 degrees Fahrenheit! Now that is hot!! Magma is so hot, that it is 30% as hot as the sun. After magma erupts out of a volcano, it is now called lava. When lava first comes out of a volcano it is liquid, and can be from 1,300 – 2,200 degrees Fahrenheit. Volcanoes also erupt when huge sections of the earths crust move. The sections are called plates. The plates move on magma inside the earth. They don’t move much, only about as fast as your fingernails grow! Volcanoes may erupt in four different ways: 1.) Thin fluid magma oozes from cracks but does not explode. 2.) Slightly thicker magma traps gasses. Pressure builds until ash and rock explode through the volcano's opening, while debris builds a volcanic cone. 3.) Thicker, more pasty magma forms a plug dome in the volcano’s opening. When the dome bursts, it releases hot ash and rocks that rush down the volcano’s slopes. 4.) The thickest magmas, large amounts of gas build pressure. When the gas breaks through the surface, it shoots ash and rocks miles high. When lava comes out of a volcano it is called a lava flow. Lava flows destroy everything in their path. But most lava flows travel slowly, so people can get out of the way. Another hazard that volcanoes produce are pyroclastic flows. A pyroclastic flow is a hot fast moving dust storm that is a mixture of ash, rocks, and gas that is formed during explosive eruptions. A famous pyroclastic flow came in 1980 from Mt. St. Helens in Washington state. When Mt. St. Helens erupted, it sent a pyroclastic flow 16 miles from the volcano in all directions. It only took 10 minutes for the flow to travel 16 miles. Now that’s fast!! There are thousands of volcanoes around the world. Some erupted millions of years ago, but others are still erupting today. Volcanoes that are still erupting today are called “Active” volcanoes, and volcanoes that do not erupt anymore are called “Dormant” volcanoes. Now that we know about volcanoes and what they can do, lets review what we have learned. WOW! What a great adventure we had! I hope you had fun learning new things today, I know I did.