The message inside the ice
Un pequeño experimento revela cómo se mueve el agua.
When Leo drops an ice cube into his drink, he notices something that has always seemed ordinary: the ice floats. His older sister, Ana, suggests that they investigate rather than simply accept it as a fact. She explains that freezing changes the arrangement of water molecules. In ordinary liquid water, the molecules can move around one another. In ice, they form a more open structure, so the same amount of water occupies a greater volume. Because its density is lower, ice floats on liquid water. Leo observes the cube slowly melting. Ana asks whether any water has vanished. He realises that the solid has become liquid, even though the material itself is still present. For a second experiment, they pour water into a freezer-safe container and leave room for expansion. By the following morning, the frozen water takes up more space. Ana explains why a completely full, sealed glass container would be unsafe in a freezer. They then discuss winter lakes. Ice commonly forms at the surface, while deeper water may remain liquid. This is important for aquatic life because fish and other organisms can survive beneath the frozen layer. Leo writes down his observations and draws a diagram. A floating ice cube is no longer just something that keeps his drink cold; it is evidence of an unusual property of water with important consequences for living things.