What are pillow lavas?

Pillow lavas are like coconut cookies that lava makes when it cools down underwater.

Imagine you're baking a cookie and you drop it into cold milk, splat! It plops in, and the hot cookie cools quickly, making a soft, round shape. That's kind of what happens with pillow lavas. When lava flows from a volcano into the ocean, it meets cold water, and instead of spreading out flat like a pancake, it forms round, bubbly shapes, like pillows.

When lava hits the ocean, it cools really fast because of the cold water. This quick cooling makes the outside of the lava harden quickly, while the inside is still soft and flowing. These pillow-shaped rocks are formed one after another, sometimes stacking up like layers of cookies in a jar.

If you ever touch a pillow lava rock, it might feel rough on the outside but smooth on the inside, just like how a cookie can be crispy on the outside and gooey on the inside. Scientists love studying them because they tell us about ancient oceans and volcanoes that were underwater long ago!