ELI5: Explain Like I'm 5

Bottlebrush (cave formation)

Okay, so you know how some rocks can be really cool shapes, like a crazy hat or a silly face? Well, sometimes inside caves, there can be really cool shapes that form too!

One of these shapes is called a "bottlebrush." It looks like a brush with a lot of bristles sticking out, but instead of being made of plastic or hair, it's made of minerals.

So how does it form? Well, when water drips into a cave, it can be carrying minerals like calcium or magnesium. These minerals stick to the cave walls and start to build up over time.

But just like how a real brush has parts that stick out and parts that are more flat, the cave walls have different shapes and angles too. Some parts of the wall might stick out more and get more drips of water, while other parts might be flatter and get less water.

When the minerals start to build up, they follow the shape of the cave wall. So the parts that get more water will get more minerals, and the parts that get less water will get less minerals. When these mineral deposits build up over time, they can form a bottlebrush shape!

It's really magical to see these formations in person, but it takes a lot of patience and time for them to form. It's almost like art that's made by nature itself!