Scientists Say: Magma and lava

Magma refers to molten rock underground, while lava describes molten rock that has reached Earth’s surface

Lava is molten rock that seeps up through cracks in Earth’s crust or erupts out of volcanoes. When this piping hot goo hardens and cools, it forms igneous rock.

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Magma (noun, “MAG-muh”), Lava (noun, “LAH-vuh”)

Both of these words describe molten rock. The difference is where that melted rock is located. Magma is molten rock deep underground. Much of Earth’s mantle is made of magma. That magma can rise up through Earth’s crust and erupt out of volcanoes. Molten rock that has reached Earth’s surface is called lava. Depending on its chemical composition, lava can be runny like syrup or so thick it barely flows at all. This molten material is still called lava once it has cooled and hardened. The solid rock is known as igneous rock. The formation of igneous rock is part of Earth’s rock cycle. In this cycle, plate tectonics, weathering and other processes continually transform Earth’s rocks from one type to another. The three types are igneous, sedimentary and metamorphic rock.

In a sentence

During an eruption in 2018, Hawaii’s Kilauea volcano gushed out enough lava to fill a football stadium 1,000 times over. 

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Maria Temming is the assistant editor at Science News for Students. She has bachelor's degrees in physics and English, and a master's in science writing.

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