What is the difference between "magma" and "lava"?

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Episode Number: 100

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Location Taken: US

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Welcome to CoreFacts, where we're always short on time and big on science. I'm Danielle Eganhouse.  Today's question is an interesting one.

What is the difference between "magma" and "lava"?

Scientists use the term magma for molten rock underground and lava for molten rock 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.

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