Volcanoes

A volcano is a mountain that actually builds itself. Scientists think that far down in the earth, where it is fiercely hot, there are pockets of melted rock. It is though that the pressure of gas pushes this melted rock, called magma, up, out of the ground. Once magma comes to the surface it is known is lava. Lava may be thick like syrup or as thin as watery soup, but it cools into a black, gritty rock. It is this rock that builds the volcano. As the lava pours out of the earth, it piles up into the shape of a cone, with a tunnel running down its center. The more lava comes out, the higher and wider the volcano gets. A volcano can erupt in different ways. One kind shoots a stream of glowing lava high into the air, like a giant, fiery fountain. Another launches solid chunks of red-hot rock and cinders. Some volcanoes pour rivers of lava through cracks in their sides. And some blow themselves to pieces!

There are several thousand volcanoes in the world. Most of them are extinct that means they do not erupt any more. Some others are dormant, which means sleeping, and although they are silent at this moment, they may erupt again at any moment. About 500 volcanoes are active all the time. Volcanoes have killed many people and destroyed whole cities. However, the products of an erupting volcano can be profitable for farmers who live around the volcano. They make the land fertile and that is good to produce good crop. That is also the reason why people continue to live close to the volcano, although it is dangerous. The volcano can make a farmer wealthy.