Answer:
Scientists use the term magma for molten rock underground and
lava for molten rock (and contained gases) that breaks through
the Earth's surface. Originating many tens of miles beneath the
ground, magma commonly contains some crystals, fragments of
surrounding (unmelted) rocks, and dissolved gases, but it is
primarily a liquid composed principally of oxygen, silicon,
aluminum, iron, magnesium, calcium, sodium, potassium, titanium,
and manganese. Lava is red hot when it pours or blasts out of a
vent but soon changes to dark red, gray, black, or some other
color as it cools and solidifies. Very hot, gas-rich lava
containing abundant iron and magnesium is fluid and flows like
hot tar, whereas cooler, gas-poor lava high in silicon, sodium,
and potassium flows sluggishly, like thick honey in some cases
or in others like pasty, blocky masses.
