Ice is less dense than liquid water.

Ice is less dense than liquid water.

• A. True
• B. False
• C. Cannot be determined
• D. Only at high pressure

Answer: (A)

Density is mass per volume. Ice forms a crystalline lattice of water molecules held together by hydrogen bonds, which creates more open space between molecules. In liquid water, molecules move more freely and can pack more closely, making the liquid denser. Because the frozen structure occupies more volume without adding mass, ice has a lower density than liquid water, so it floats. For reference, ice is about 0.92 g/cm³ and liquid water is about 1.00 g/cm³ at typical temperatures. Note that at very high pressures some ice phases can be denser than liquid water, but under normal conditions the statement holds true.

Density is mass per volume. Ice forms a crystalline lattice of water molecules held together by hydrogen bonds, which creates more open space between molecules. In liquid water, molecules move more freely and can pack more closely, making the liquid denser. Because the frozen structure occupies more volume without adding mass, ice has a lower density than liquid water, so it floats. For reference, ice is about 0.92 g/cm³ and liquid water is about 1.00 g/cm³ at typical temperatures. Note that at very high pressures some ice phases can be denser than liquid water, but under normal conditions the statement holds true.