WATER ESSAY
The first thing water reminds us of is the clear liquid in our water bottles. However, water is more than a normal substance. Water is the beginning and the continual of life on earth. Because of its many unique properties, water was able to start life on our planet. Water covers about 3/4 of the earth. In nature, water naturally exists in all three physical states of matter—solid, liquid and gas. Water's extraordinary properties are emergent properties resulting from water's structure and molecular interactions. Living cells are 70%-95% H2O The simple structure of H2O is the source of all water's properties. With two hydrogen atoms sticking to an oxygen atom in a tetrahedron shape, water is considered as a polar molecule. Because oxygen is very electronegative, it pulls hydrogen's electrons towards it, causing oxygen to become partial negative. The hydrogen atoms then will have fewer electrons towards its own nucleus, therefore making it partial positive. Since positive charge and negative charge attracts each other, the molecular formation of H2O will result hydrogen bonding. Each water molecule can form hydrogen bonds to a maximum of four other water four molecules. Organisms Depend on the Cohesion of Water Molecules Hydrogen bonds hold water molecules together. When water is in liquid form, its hydrogen bonds continually break and re form. Molecules are continually forming re-form. new bonds with other water molecules. As a result, most of the water molecules are bonded to their neighbors, which makes water more structured than other liquids. The hydrogen bonds hold the substance together in the phenomenon called cohesion. cohesion Since the hydrogen bonds connect water molecules together, water can reach the bonds leaves of plants through microscopic vessels extending from the roots. When water evaporates from a leaf, it is replaced by water in the vessels of the leaf. Hydrogen bonds cause the water leaving the