Which statement correctly explains why ice floats on liquid water?

• A. Ice is denser than water
• B. Ice is less dense than water
• C. Water has no surface tension
• D. Ice sinks

Answer: (B)

Density and buoyancy drive this. An object floats when its density is lower than the liquid it’s in. Ice forms a rigid, open crystal lattice that holds water molecules further apart than in liquid water, so its density is lower (about 0.92 g/cm³) than that of liquid water (about 1.00 g/cm³ at typical temperatures). Because ice is lighter per unit volume, it displaces a volume of water whose weight matches or exceeds its own, creating an upward buoyant force that makes it float. The other ideas aren’t correct here because sinking would happen if ice were denser; surface tension isn’t the primary mechanism for floating, and ice sinking contradicts what we observe.