Question

solid water floats on liquid water. why does this happen?
ice is less dense than liquid water
ice is less dense than water vapor

Explanation:

To determine why solid water (ice) floats on liquid water, we use the principle of density and buoyancy. An object floats in a fluid if its density is less than the fluid's density.

• For the first option: Ice (solid water) has a density of about \(0.917\ \text{g/cm}^3\), while liquid water has a density of about \(1.0\ \text{g/cm}^3\). Since \(0.917< 1.0\), ice is less dense than liquid water, which explains why it floats on liquid water.
• For the second option: Water vapor (gas) has a much lower density than ice (solid). Comparing ice's density to water vapor's density is irrelevant to why ice floats on liquid water (we need to compare ice's density to liquid water's density, not water vapor's).

Answer:

A. Ice is less dense than liquid water