2. A volcano is an
opening, or rupt
ure, in a
Planet’s
crust, which
allows
hot magma, Lav
a flow, volcanic
ash and gases to
escape from the
magma
chamber below
the surface.
14. When rock inside the Earth becomes hot enough it melts.
This molten rock, or magma, is less dense than the
surrounding
solid rock. Just as an object that is less dense than water will
float
on water, the relatively low density of the magma cause it to
rise
to the surface of the Earth.
If the magma contains water and dissolved gases, when the
magma
reaches the surface the water and dissolved gases will
suddenly expand
into steam and gas, causing a violent eruption.
