Concept:Buoyancy dictates that a less dense object will float in a denser fluid. The density of ice is lower than that of liquid water.
Formula:$$ \text{Density} = \frac{\text{Mass}}{\text{Volume}} $$
Solution:- In the liquid phase, water molecules dynamically slide past each other, packing relatively closely together.
- When freezing into ice, hydrogen bonds dictate a strict, hexagonal crystal lattice.
- This lattice forces the molecules to sit further apart, creating permanent "empty spaces" or voids within the structure.
- Because the volume increases by roughly 9% without a change in mass, the density drops, causing the ice to float.
Why other options are incorrect:Ice has a hexagonal, not cubic, structure. The intermolecular forces are actually highly stable and rigid, not weak. The primary physical cause of the volume expansion is the geometrical empty spaces.
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