Question

What happens as water freezes?

Answer 1

Hint: Water is a liquid that consists of intermolecular hydrogen bonding. A liquid has atoms which are loosely bound to each other, while in solids they are packed with each other. There are different phase changes when a solid is subjected to high temperature. It changes to liquid and then gas, and vice versa when subjected to low temperature.

Complete answer:
As we know, the atoms in a solid are very packed with little or no movement so no kinetic energy. In a liquid state the water molecules possess’ energy as they have a tendency to flow due to the loosely packed atoms.
The water molecules consist of hydrogen bonding, in liquid state these molecules are in constant motion and move closely to each other as the water has the ability to flow. Now, when the temperature is reduced, the molecules of water lose their kinetic energy and do not move around as freely as earlier in the liquid state. This results in the phase transition from liquid to solid and the water freezes and becomes ice. In ice the bonds of water molecules have more length that makes molecules apart from each other in the crystal packing.
As the liquid water becomes ice, it forms a packed crystal lattice structure in which the molecules have larger bonds and are packed as in solids. The removed heat has resulted in making the water particles to come close to each other and form stronger bonds and attractive forces. They do not come close to each other as in flowing in a liquid state.
Hence, as water freezes, it removes its kinetic energy and gives rise to a closely packed structure due to strong forces, which is called ice.

Note:
The temperature at which water starts to freeze is called its freezing point which is 0 degree Celsius. The fact that ice floats on water is due to the reason that water molecules in liquid state are close to each other and in ice they have large differences to each other that makes them less dense than water and allows ice to float on water.