Why is this the answer?

The answer is iceberg because this clever riddle uses amazing facts about frozen water to describe one of the biggest and most mysterious objects in the ocean. It is a wonderful word puzzle that helps you think about science in a brand new way. The riddle has two important clues, and we can look at each one like a detective solving a case. The first clue is Lighter than what I am made of. This is the cool science trick. An iceberg is a giant piece of floating ice. Ice is just frozen water. When water freezes and turns into solid ice, it actually gets a little bit bigger and lighter than the liquid water around it. Because the ice is lighter than the liquid water it is sitting in, the whole iceberg floats up to the top! It is the same reason an ice cube floats in your glass of juice. The riddle writer is pointing out this wonderful scientific difference between water and ice. The second clue is More of me is hidden Than is seen. This is the most famous part of the puzzle. When you look at an enormous iceberg floating in the ocean, the part you can see above the water is huge. But guess what? It is only a tiny part of the whole thing! Scientists know that most of the iceberg, which is about nine tenths of its entire size, is actually hiding underwater. That means the small bit you can see is nothing compared to the massive block of ice that is secretly sitting underneath the surface of the water. The riddle makes a giant, cold object sound like a fun secret waiting to be discovered, and its two best clues are perfect facts about how ice and water work together in the natural world.