Upwelling (noun, “UP-well-ing”)
This is a process in which one substance rises up through another substance, and then flows outward above it.
In the ocean, for example, surface winds can push warm water away, allowing colder water beneath to rise. The cold water, which is full of nutrients, spreads out on the surface as the warm water moves away. The nutrients then feed plankton and other small organisms, which in turn feed bigger ones such as fish and whales.
Upwelling also happens beneath the surface of the Earth. But there, instead of something cold rising, something hot comes up instead. Really hot. Inside the Earth’s mantle, fiery liquid rock slowly swirls. This hot rock is less dense than the cooler, solid rock above it. As tectonic plates — the moving slabs that make up the Earth’s outer layer — shift around, the liquid rock rises. At the surface, it spreads out, cools and becomes solid. This upwelling adds rocky material to the planet’s crust.
In a sentence
On Jupiter, there is upwelling of clouds in the atmosphere — big stinky clouds of ammonia.
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