All About Volcanoes for Children: Introduction to Volcanoes for Kids – FreeSchool

You’re watching FreeSchool! The Earth is covered with a variety of different
features. Oceans, plains, rivers, valleys, mountains,
and one of the most dramatic, volcanoes. Named for Vulcan, the Roman god of fire, Volcanoes
are one of the most powerful, spectacular forces on earth. Volcanoes can build, or destroy – but where
do they come from? The surface of the Earth is cool and solid,
but underneath, a thick layer of hot, molten rock churns. This molten rock is called magma. Sometimes, a crack or a break in the cool
surface layer – known as the crust – allows magma to rise to the surface. There are two main ways that volcanoes are
formed. First, volcanoes may form at the boundaries of tectonic plates. Tectonic plates are sections
of the earth’s crust that float on the layer of magma beneath, known as the mantle. Where
two plates meet, they may either pull apart, allowing magma from the mantle to come up,
or they may push together, shoving some of the crust beneath to be melted into magma
and pushing other pieces of the crust up to form new mountains. The new magma beneath
the crust starts creating pressure, and once enough pressure has built up it can burst
through the crust – – as an erupting volcano. The second way volcanoes may form is due to
‘hotspots.’ Scientists believe that when a volcano forms away from the edge of a tectonic
plate, it is either because the mantle beneath is unusually hot, or because the crust in
that area is unusually thin, allowing the magma to melt its way through to the surface.
Magma that reaches the surface is called ‘lava.’ Either way, the result is the same: Volcanoes! Volcanoes are typically mountains, and although
you may picture a volcano a certain way, they actually form a variety of different structures. The first type of volcanoes are cinder cones.
Cinder cones are some of the most common volcanoes. They are fairly small, steep-sided cones,
made of loose rocks, ash, and debris that were thrown out during the eruption. Unlike
other volcanoes, cinder cones usually have a single opening through which magma escapes. The second type of volcanoes are shield volcanoes.
Shield volcanoes have low profiles and shallow-sloping sides. Unlike cinder cones, shield volcanoes
can be very, very large because they are so short and wide – they are the largest type
of volcanoes on earth – but they are usually less dangerous than other types. That’s because
instead of forceful eruptions, shield volcanoes are formed by very runny lava that flows a
long way. Third, there are composite volcanoes. Also
known as ‘stratovolcanoes’ because they are made of alternating layers built up through
different eruptions, composite volcanoes can grow to be very large and may be very dangerous.
Some famous volcanoes, like Mt Fuji in Japan, and Mt Vesuvius in Italy, are
composite volcanoes. There are other types of volcanoes, too, like
fissure vents, lava domes and lava tubes. When the lava from volcanic eruptions cools,
it hardens into rock. These rocks are igneous, or formed from magma and lava. Different types
of lava, different types of eruption, and different speeds of cooling all produce different
kinds of rock. One interesting type of volcanic rock is called pumice. Pumice is full of little
air bubbles, which makes it so light that it can actually
float on water. Another interesting type of volcanic rock is obsidian. Obsidian is hard
and shiny, like glass, and can be made into blades and tools with a very sharp edge. There
are many other types of volcanic rock, as well! Volcanoes that may still erupt are called
active. Volcanoes that will probably not erupt again any time soon are called dormant – a
word that means ‘sleeping.’ Scientists have gotten better at predicting
when a volcano is going to erupt, but sometimes volcanoes still take people by surprise. Beautiful
and dangerous, volcanoes are an important part of our living world. They can create
new land, they can destroy and even kill…but in the end, they are a powerful reminder that
our planet is still wild, and always changing. I hope you enjoyed learning about volcanoes
today. Goodbye till next time!

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