Which statement correctly describes the density relationships among ice, liquid water, and seawater?

Which statement correctly describes the density relationships among ice, liquid water, and seawater?

• A. Ice is less dense than seawater; seawater is denser than freshwater; ice will float.
• B. Ice is denser than liquid water.
• C. Ice sinks in seawater.
• D. Ice has the same density as seawater.

Answer: (A)

Density differences explain why ice floats and seawater behaves as it does in water. Ice has a crystal structure with more open space, making it less dense than liquid water. Seawater is denser than freshwater because the dissolved salts add mass per volume. Since ice is less dense than seawater, it will float on seawater, just as it does on freshwater. Typical values help visualize this: ice around 0.92 g/cm³, freshwater about 1.00 g/cm³, seawater about 1.025 g/cm³. So the statement that ice is less dense than seawater, seawater is denser than freshwater, and ice will float is the correct description. The other ideas—ice being denser than liquid water, ice sinking in seawater, or ice having the same density as seawater—don’t match these density relationships.

Density differences explain why ice floats and seawater behaves as it does in water. Ice has a crystal structure with more open space, making it less dense than liquid water. Seawater is denser than freshwater because the dissolved salts add mass per volume. Since ice is less dense than seawater, it will float on seawater, just as it does on freshwater. Typical values help visualize this: ice around 0.92 g/cm³, freshwater about 1.00 g/cm³, seawater about 1.025 g/cm³. So the statement that ice is less dense than seawater, seawater is denser than freshwater, and ice will float is the correct description. The other ideas—ice being denser than liquid water, ice sinking in seawater, or ice having the same density as seawater—don’t match these density relationships.