Water

 

Water has many unique characteristics that make it vital for living organisms. The essence of water is its versatility, its necessity, and its ubiquity.

It covers about 71% of the planet's surface and makes up about 60% of the human body. 

Water can exist in three states: It is the only common substance that exists in all three states of matter: solid (ice), liquid (water) and gas (water vapor), at normal Earth temperatures and pressures.

Water is essential for many biological processes, such as photosynthesis, respiration, digestion, circulation, excretion, reproduction and more. Water also plays a key role in shaping the Earth's landscape, weather and climate. Water cycles through different reservoirs, such as oceans, rivers, lakes, glaciers, clouds, rain and snow, by processes such as evaporation, condensation, precipitation, runoff and infiltration.

Only about 2.5% of the Earth's water is freshwater, and most of it is locked in ice caps, glaciers and underground aquifers. Only about 0.01% of the Earth's water is readily available as surface water in lakes, rivers and streams.

Components of Water:

Water is a chemical compound composed of two hydrogen atoms and one oxygen atom, which are bonded together by covalent bonds.  The ratio of hydrogen to oxygen atoms in water is 2:1, meaning that for every oxygen atom, there are two hydrogen atoms. It has the molecular formula H2O.

Water is a simple molecule, composed of two hydrogen atoms and one oxygen atom. However, the way these atoms are arranged and bonded gives water some extraordinary characteristics. Water molecules have a bent shape, with an angle of 104.5 degrees between the two hydrogen atoms and the oxygen atom.  This shape gives water some unique properties, such as polarity, cohesion, adhesion, and surface tension. 

Properties of Water:

Water is essential for life, yet it also has many unique and mysterious properties that defy easy explanation. Some of these properties are:

- Water is a universal solvent, meaning it can dissolve many other substances. Water's solvency is crucial for life, as it allows nutrients, minerals, gases and wastes to be transported and processed in cells and organisms.

- Water has a high specific heat capacity, meaning it can absorb or release a lot of heat without changing its temperature much. This helps regulate the temperature of living organisms and the environment.

- Water can change from one state to another by absorbing or releasing heat energy. Water can also undergo phase changes, such as melting, freezing, evaporating, condensing, and sublimating, by absorbing or releasing heat energy.

- Water has polarity. Water molecules have a slight electric charge, with the oxygen atom being slightly negative and the hydrogen atoms being slightly positive. This makes water molecules attract each other and form hydrogen bonds, which are weak but numerous. Hydrogen bonds give water its cohesion (the tendency to stick together) and adhesion (the tendency to stick to other surfaces). Water has a high surface tension, meaning it tends to stick together and form droplets or bubbles. These properties allow water to form drops, flow, climb up plants and dissolve many substances.

- Water has a high latent heat of vaporization, meaning it requires a lot of energy to evaporate. This helps cool living organisms and the environment by sweating or transpiration.

- Water is less dense as a solid than as a liquid, meaning ice floats on water. This prevents water from freezing completely and allows life to exist under frozen surfaces.

Life without water: a grim scenario for our planet

But what if water suddenly disappeared from our planet? What would happen to life and the environment? How long could we survive without water? We will explore some of the possible consequences of a world without water.

The first thing that would happen is that all the liquid water on the surface would evaporate into the atmosphere. This would create a thick layer of clouds that would block out most of the sunlight. The temperature would drop drastically, creating a global ice age. The oceans would freeze over, trapping most of the salt and minerals. The ice would reflect more sunlight, further cooling the planet.

The lack of water would also affect the air we breathe. Without water, plants and algae would die, reducing the oxygen production. The carbon cycle would be disrupted, leading to a buildup of carbon dioxide and other greenhouse gases. The air would become more acidic and toxic, making it hard to breathe.

Without water, most living organisms would die within a few days. Humans can only survive for about three days without water, depending on the conditions. Animals would also suffer from dehydration, starvation, and exposure. Some microorganisms, such as bacteria and fungi, might be able to survive in extreme environments, such as deep underground or in volcanic vents. However, the diversity and complexity of life would be greatly reduced.

Without water, there would be no erosion or weathering of rocks and soil. The landscape would become barren and rugged. There would be no rivers, lakes, or glaciers to carve out valleys and basins. There would be no soil formation or nutrient cycling. The Earth would look like a dry and dusty rock.

Without water, there would be no life as we know it. 

Summary:

Water is essential for life, and it is a versatile and abundant substance. It covers about 71% of the Earth's surface and makes up about 60% of our body weight. Water is involved in many biological processes, such as photosynthesis, respiration, digestion, circulation, and excretion. Water also regulates the climate, transports nutrients and wastes, and shapes the landscape.

Points to Ponder:

Why water has specific properties that makes possible basic life functions?

What if water molecules have no bent or have much greater bent than its current 104.5 degrees?