Which property explains why water weighs more than ice at equal volumes?

• A. Density
• B. Color
• C. Viscosity
• D. Temperature

Answer: (A)

Density is the amount of mass packed into a given volume. At equal volumes, the substance with higher density contains more mass and thus weighs more under gravity. When water freezes into ice, its molecules arrange in a open crystal lattice that spaces them out more, making ice less dense than liquid water. So the same-sized block of water has more mass than the same-sized block of ice, explaining why water weighs more per unit volume. Color and viscosity don’t determine how much matter is in a volume, and while temperature can influence density, the direct reason is that liquid water is denser than ice.