Dr. Universe explains why Earth has lava inside

Washington State University's resident feline scientist, Dr. Universe, dives deep beneath Earth's surface to answer a big question from Nora, 6, of Florida: Why does Earth have lava in the middle?

With help from WSU geologist Johannes Hämmerli, Dr. Universe explores what's inside the planet, from the solid metal core to the swirling liquid outer core and the slowly flowing mantle. Readers learn how heat, pressure, and even water can melt rock into magma, why that magma rises toward the surface, and how it becomes lava when it erupts from a volcano. The column also shows how scientists use earthquakes to study Earth's interior, even though humans have only drilled a few miles into the planet.

Ask Dr. Universe is a science education project from WSU that answers real questions from curious kids around the world. Readers and listeners can submit their own questions and explore more columns, videos, and the Ask Dr. Universe podcast online.