Every day seashells wash up on beaches all over Earth like treasures from a secret world beneath the waves Spiraled or spiky round or ridged shells come in all sorts of shapes and sizes and all the colors of the rainbow That’s because seashells have so many different jobs to do
Seashells can rise and sink like a submarine A nautilus floats because most of its shell is filled with a lightweight gas To dive down it pumps water into its shell When the nautilus wants to rise toward the surface it lets water flow out of its shell gas chambers water
