Why is this the answer?

The answer is ice because this amazing riddle is a secret code about how strong and how weak something can be at the very same time. First, let us look at the beginning of the riddle: "Power enough to smash ships and crush roofs." This clue tells us that the answer must be incredibly strong, like a giant. Ice can become that strong! Think about a massive iceberg floating in the cold ocean. These huge chunks of ice are like frozen mountains. When a big ship accidentally hits an iceberg, the ship can be damaged or even smashed, just like the riddle says. Also, in the winter, when a lot of heavy snow and ice builds up on the roof of a house, it can get so heavy that it crushes the roof down. Or, imagine very large hailstones, which are balls of ice, falling from the sky during a thunderstorm. They can be strong enough to break things, too. So, the first part of the riddle is talking about ice in its biggest, coldest, most powerful form. Now, let us look at the second part: "Yet it still must fear the sun." This is the part that is the cleverest clue of all. Even though ice is so strong it can hurt a giant ship or crush a roof, it has one tiny weakness: the sun. When the warm, beautiful sunlight touches the ice, the ice starts to melt. It turns from a hard solid back into water. An enormous iceberg that took hundreds of years to form can be slowly destroyed by the sun's warmth. The sun is the one thing that ice cannot fight or win against. That is why the answer is ice, because it is the only thing that is a powerful giant when it is cold, but a very weak puddle when the sun shines on it. The riddle perfectly describes how ice is strong enough to cause great destruction but is completely powerless against a little bit of heat.