How do caves form?

There are caves all over Earth. And people discover more every day!  They’re found in rock, lava, ice, and even sand. But how do caves form? We asked geologist Hazel Barton to help us find the answer. Got a deep question? Send it to us at BrainsOn.org/contact, and we’ll help explore the answer?  See omnystudio.com/listener for privacy information.