What makes h2o special

It is weaker than the bonds between the hydrogen and the oxygen but still strong enough to cause water to freeze into ice. Why does ice melt when the melting temperature is reached? The strength of the vibration increases with temperature. When the temperature is high enough, the ice melts, because the thermal vibration of the molecules becomes so strong that the hydrogen bonds are broken.

In the ice structure, the molecules have a relatively open arrangement. When the ice melts, the molecules become free to pack together more closely. That is why water is denser than ice. The water molecules in liquid water attract each other.

Inside the liquid, any particular water molecule is acted on by attractive forces from all directions. It is different for a molecule right at the water surface, however. It is attracted by molecules below it and beside it, but not from above. This makes the surface tend to shrink parallel to itself. This shrinkage force is called surface tension. Have you ever watched a soap bubble being made by waving a bubble wand?

This density trait is the engine for convection, one of the most important elements of the climate system; cold, salty water is heavy and sinks to great depths. It is replaced by water flowing in at the sea surface. This is called a dipole. It thus behaves differently from other substances in many ways. Ice is less dense and floats on the surface. Freshwater has its greatest density at four degrees, and sinks to the bottom. This is then overlain by warm water.

Salty water has different characteristics. Back to the page of origin Water — a unique molecule. Oxygen also has two unshared pairs of electrons, thus there are four pairs of electrons surrounding the oxygen atom, two pairs involved in covalent bonds with hydrogen, and two unshared pairs on the opposite side of the oxygen atom. Water is a polar molecule means that there is an uneven distribution of electron density.

Water has a partial negative charge near the oxygen atom due the unshared pairs of electrons,and partial positive charges near the hydrogen atoms. An electrostatic attraction between the partial positive charge near the hydrogen atoms and the partial negative charge near the oxygen results in the formation of a hydrogen bond.

And the ability of ions and other molecules to dissolve in water is due to polarity. The slight positive charges on the hydrogen atoms in a water molecule attract the slight negative charges on the oxygen atoms of other water molecules.

This tiny force of attraction is called a hydrogen bond. This bond is very weak. Hydrogen bonds are formed easily when two water molecules come close together, but are easily broken when the water molecules move apart again. They are only a small fraction of the strength of a covalent bond, but, there are a lot of them and they impart some very special properties to the substance we call water. Water is a Liquid at Room Temperature. Over three-quarters of the planet earth is covered with water.

Life probably started in such a liquid environment and water is the major component of living things humans are over 60 percent water. At room temperature anywhere from zero degree centigrade to degrees centigrade , water is found in a liquid state.