Physical structure and property of water and its role in life

Water plays a vital role in the survival of different organisms. Water is said to occupy more than 70% of the earth’s surface and occupies approximately 60% of volume in plants and animals. Without water human and all life existence would be impossible. The diagram below shows the structure of a molecule of water, it is formed by the bonding of two hydrogen atoms to a central oxygen atom.

Looking at the diagram above one can see how the hydrogen atoms are bonded to the oxygen causing a polarity in the molecule; it is this polarity that causes more molecules to attract to each other through strong molecular bonds. When water changes phase the molecules are arranged differently this is further explained in the topic Different States of matter

Here are some physical properties of water and how they relate to their role and functions:

1.  Water is a universal solvent: - This means it is capable of dissolving a wide variety of chemical substances, this feature allows water to carry solvent nutrients from infiltration, ground water flow, runoff and in different living organisms.
2. Water is a Good Conductor of Heat: - It is said to conduct heat better than any other liquid except mercury. This feature is especially useful to lakes and other large water bodies; this allows them to maintain a uniform vertical temperature profile.
3. Water has a High Surface Tension: - Meaning it has an elastic as well as adhesive structure. This allows it to aggregate in drops and not to spread over a surface as a thin film. It also sticks to the sides of vertical surfaces and not fall due to gravity. This feature is especially useful to plants, it enables them to move water from the roots to their leaves, and also the movement of blood in blood vessels in animals.
4. Water has a high Specific heat: - The specific heat of a substance is the amount of heat required to change its temperature, therefore seeing that it has a high specific heat capacity it has to absorb allot of energy to get hot which takes quite some time and also releases energy slowly when in a cool setting. This helps to explain why sea breeze occurs at day but land breeze occurs at night, because it has a higher specific heat. This also helps in the moderation of the earth’s climate and also in the regulation of body temperature.
5. Water has a neutral pH in the pure state: - This feature enables it to be neither acidic nor basic but changes pH when added to another substance
6. Water is able to remain liquid over a wide range of temperatures 0-100 degrees Celsius: - This feature is of great importance because it is able to remain in the liquid form in most places on earth.