The lower density of ice compared to liquid water does not only mean that ice cubes float in your water cup. This property of water is important for life on Earth because both
all the water on Earth's surface, is an essential part of the Earth system. It interacts with
liquid water and ice are part of Earth's hydrosphere. The hydrosphere, which contains
the atmosphere and biosphere in many ways. For example, large pieces of floating ice
provide penguins, polar bears, and walruses with a resting place as they look for food in
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Water on Eart
the ocean.
3. Think about what happens in the hydrosphere and biosphere when ice forms at the
top of a lake. What might happen instead if ice were denser than liquid water?