The Great Lakes of the United States are often covered with a sheet of ice every winter. Which best explains why this ice does not sink to the bottom?

Ice floats because it is less dense than liquid water. When water freezes, its molecules form a structure that takes up more space, so the same amount of water has lower density as ice. Therefore, the ice stays at the surface rather than sinking to the bottom; the correct choice is “Ice is less dense than water.”

AI-written and checked against the verified answer.