Buoyancy is a force that causes lighter material to rise through surrounding denser material. The hot liquid magma rises towards the surface through the more dense rock.

浮力是密度较高的物质把密度较低的物质往上升的力量，所以炽热的岩浆会通过密度较高的岩石上升到地面。

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The rest of the vertical column is made from a material called syntactic foam - a solid made mostly of hollow "microballoons" - giving it enough buoyancy to float back up.

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