Water is the fluid of most living organisms on Earth. It is vital for all forms of life. Water comes from Old English “waeter. It’s frequently dubbed the “universal solvent”. Since in the wate rmolecule the oxygen atom has a higher electronegativity than the hydrogen atoms.

Henry Cavendish showed that water was composed of oxygen and hydrogen in 1781. The study of water on earth is called hydrography, which is about 70% of the earth’s surface, with 95% of it being in the oceans.

Water is two atoms of hydrogen, and one atom of oxygen being h20 with the oxygen having a slightly negative charge, and the hydrogens a slightly positive charge.

The hydrogen atoms have a slight positive charge, and the oyxgen atoms have a slight negative charge meaning, the hydrogen of one h20 unit sticks to the oxygen in another molecule meaning all the molecules of h2o tend to stick together. This is called “hydrogen bonding”.

Water has the strongest attraction of any non metallic liquid. The way water droplets hold together is called “cohesion” which means when particles of the same substance stick together. There are some surfaces which water prefers to stick to, one example being adhesion. Water will spread out on glass, and this is called adhesion, because adhesive forces between the water and the glass are stronger than the cohesive forces between the water molecules.

Capillary action is the ability of water to go up against gravity in narrow spaces such as up in a glass dropper as the adhesive force between the water and the glass dropper is stronger than the cohesive force bewteen the water molecules, hoever the cohesive action of the water molecules draws more water up and into eventually filling the dropper. It’s believed this was first observed by Leonardo Da Vinci.

Water when freezes turns into the solid we call “ice”. Ice floats on the surface of the water because it is less dense than water, hence takes up more space.

For the life of humans people have debated how much water is needed for life. This estimation has varied greatly, although we know activity, temperature, humidity and other factors all play a role. It’s estimated the kidneys can excrete up to one litre of water per hour. The heavier water displaces the lighter ice.

Water also has heat capacity which is why it is commonly used for heating and cooling.

Water has a high surface tension, which is caused by the strength of the bonding of the hydrogen molecules between water molecules. This allows insects to walk on water.

Water is believed to tbe the most abundant molecule in the universe, and the third most abundant in the inverse after h2 and co (carbon monoxide).

Water can act as an acid or base (alkaline) in reactions. Some people think of an acid as being a proton donor, and a base as a proton acceptor.

Substances that dissolve in water are called “hydrophilic” meaning they have an affinity for water. They are polar, their polarity is stronger than the cohesive forces in the water so instead of bonding to each other the water will bond around these substances.

When something is hydrophobic, it doesn’t have an affinity to dissolve in water. They are not polar, they don’t have charged poles. The water’s cohesive forces is stronger.