Listening to Shells

There is a small fountain and a basket of shells right outside the door of Peter's daycare. Every morning, he puts a couple of shells in the fountain. It is one of his favorite things to do.



This morning, he picked up the shells to listen to the sounds they make.



I always thought you could hear the sounds of the sea inside a shell. Apparently, Peter hears something else.



And just in case you have trouble understanding Peter, a translation of the conversation can be found in the comments.