Why Is Water More Dense Than Ice?

by Jay | Updated on December 18th, 2022

Water is unique in achieving its optimum density as a liquid rather than a solid. This implies that ice floats on water. A material’s density is described as its mass per unit volume.

The density of all compounds varies with temperature. The density of a substance does not shift with temperature, but the amount or area where it fills does.

photo of icebergs during daytime

If the temperature rises, the acceleration of molecules increases, and they consume more electricity. This expands the distance between molecules of certain fluids, leaving warmer liquids less compact than colder solids.

If we put the same amount of water and ice in the same bottle, water would weigh more than ice. The explanation is that water is denser than ice and takes up less volume than ice. As a result, ice floats on water when its mass is lower than water.

The Hydrogen Bonds

In water, however, hydrogen bonding cancels out this impact. Hydrogen bonds bind each water molecule to approximately 3.4 other water molecules in liquid water. As water freezes into ice, it crystallizes into a solid lattice, increasing the distance between molecules, with each molecule hydrogen bound to four others.

What about “heavy ice”?

We already mentioned that ice floats on water when it is less solid, yet some types may be denser than ordinary water. Since ice is formed from “heavy water,” it is 10.6 percent denser than regular water.

Heavy vapor, D2O instead of H2O, is water in which all hydrogen atoms have been substituted by deuterium, a hydrogen isotope with one proton and one neutron.

Strong water is thicker than ordinary water (which normally has a trace amount of heavy water molecules), and heavy-water ice can sink in ordinary water. Since ice is less compact than water, it may float on the shore.

  • When water is heated, the hydrogen bonds are broken by kinetic energy, allowing water molecules to escape into the air like methane (steam or water vapor).
  • As water freezes, the water molecules create a crystalline framework held together by hydrogen bonds.
  • Solid water, also known as salt, has a lower density than liquid water.
  • Since the direction of hydrogen bonds allows molecules to migrate further apart, ice has a lower density than water.
  • Other liquids solidify as the temperature drops, so their kinetic energy decreases, allowing molecules to compact more closely and making the solid denser than its liquid nature.

What if scenario: if the ice was denser than water?

As the temperature is reduced, water becomes denser until it hits its full density at 4° C. Water has the unusual property of being less dense when the temperature drops from 4° C until it freezes at 0° C. Many marine life types can withstand the winter as a result of this.

Although ice is denser than water, it would freeze and repeatedly fall until the lake was frozen. This will kill certain marine species and result in an environment of even fewer life types in reservoirs that freeze regularly.

Changes in water distribution cause vertical migration of water and nutrients inside a lake, referred to as turnover. If the ice disappears in the morning, the water at the surface gets denser as it warms to 4 degrees Celsius and falls.

Sinking water sinks to the floor, forcing nutrient-rich water at the bottom to rise. In the fall, when the surface water cools and becomes more compact, it sinks, causing the same displacement or turnover of the lake’s water.


Self assessed Germaphobe, specializing in everything water, water filters, health and nutrition. Diagnosed with Type 2 Diabetes, I've acquired immense amount of knowledge when it comes to natural, biology, and everything about human anatomy.