Water

Water: The Vital Fluid of Life

Water is an inorganic compound with the chemical formula H₂O, consisting of one oxygen and two hydrogen atoms connected by covalent bonds. It’s transparent, tasteless, odorless, and nearly colorless. But its importance extends far beyond these simple descriptions. Water covers approximately 71% of Earth’s surface, supporting life in countless ways. From the tiniest microorganisms to the largest mammals, water is essential for all known forms of life.

Water’s Role in the World Economy

Imagine a world without water. Agriculture, fishing, transportation, industry, and recreation would cease to exist as we know them. Water plays an indispensable role in our economy, supporting these vital sectors. Its solvent properties make it essential for industrial processes and everyday activities such as cooking and washing.

The Universal Solvent

Water is often referred to as the ‘universal solvent’ due to its ability to dissolve more substances than any other liquid, except nonpolar ones. This property makes it a critical component in various natural processes and human activities. From dissolving salts and hydrophilic organic molecules in living organisms to facilitating chemical reactions in industrial settings, water’s versatility is unparalleled.

Water’s States of Matter

Water exists on Earth as a solid (ice), liquid, and gas (water vapor or steam). Phase transitions occur when heat is added or removed, resulting in changes such as freezing, melting, vaporization, condensation, sublimation, and deposition.

Density Variations

Water’s density varies with temperature. At 1 atm pressure, it reaches its maximum density of 999.972 kg/m³ at 3.98 °C. Below this temperature, it expands to become less dense until it reaches the freezing point, where it has a liquid density of 999.8 kg/m³. This unique property can exert significant pressure, causing pipes to burst and rocks to crack as ice forms.

Diamagnetic Properties

Water is diamagnetic, meaning it interacts weakly with magnetic fields. Its phase transitions are well-defined: ice melts at 0 °C, and water boils at 100 °C at a pressure of one atmosphere. Even below the boiling point, water can change to vapor through evaporation, sublimation, and deposition on surfaces.

The Water Cycle

The water cycle consists of evaporation from oceans and other water bodies into the air and transpiration from land plants and animals into the air. Precipitation from water vapor condensing from the air and falling to the earth or ocean occurs in several forms: most commonly rain, snow, and hail, with some contribution from fog and dew.

Hydrology and Water Resources

Hydrology is the study of the movement, distribution, and quality of water throughout the Earth. The collective mass of water found on, under, and over the surface of a planet is called the hydrosphere. Earth’s approximate water volume (the total water supply of the world) is 1.386 billion cubic kilometres (333 million cubic miles).

Water in Aquatic Ecosystems

Aquatic life forms dominate Earth’s surface waters, with nearly all fish living exclusively in water and many marine mammals. Plants like kelp and algae grow in the water, while plankton serves as the ocean food chain’s foundation.

Water in Human Civilization

Human civilization has flourished around rivers and major waterways, such as Mesopotamia and ancient Egypt, which depended on the Nile River for survival. Rome was founded on the banks of the Italian river Tiber. Large cities like Rotterdam, London, Montreal, Paris, New York City, Buenos Aires, Shanghai, Tokyo, Chicago, and Hong Kong owe their success in part to their easy accessibility via water and the resultant expansion of trade.

Water Scarcity

The most substantial human use of water is for agriculture, which accounts for as much as 80 to 90 percent of total human water consumption. Access to fresh water is often taken for granted in developed countries, but growing economic, demographic, and climatic pressures are increasing concerns about water issues.

Water’s Impact on Health

Water is vital for life as a solvent, essential in metabolic processes, and allows organic compounds to react in ways allowing replication. In anabolism, water is removed from molecules to grow larger ones; in catabolism, it’s used to break bonds and generate smaller molecules.

Hydration Recommendations

The gram was defined in France in 1795 to be equal to the absolute weight of a volume of pure water equal to a cube of one-hundredth of a meter at the temperature of melting ice. The Kelvin temperature scale is based on the Boltzmann constant and is an absolute temperature scale with the same increment as the Celsius temperature scale.

Water Intake Recommendations

The original recommendation was 1 milliliter for each calorie of food, but the latest US dietary reference intake report recommends: Men, 3.7 liters (0.81 imp gal; 0.98 US gal) per day; Women, 2.7 liters (0.59 imp gal; 0.71 US gal) per day. Water intake recommendations vary by gender and life stage.

Water in Chemical Reactions

Water is used in chemical reactions as a solvent or reactant, but not often as a reaction solvent. It’s commonly used for heat exchange due to its high heat capacity and availability. Water has high heat of vaporization and is relatively inert, making it a good fire extinguishing fluid.

Water for Recreational Purposes

Water is also used for recreational purposes, such as swimming, waterskiing, and ice sports, as well as for exercising and relaxing. The water industry provides drinking water and wastewater services to households and industry, using various sources including springs, wells, lakes, rivers, and rainwater collection.

Water Politics

Water is a strategic resource in global politics, causing health impacts, damage to biodiversity, and affecting access to safe drinking water. By 2030, some developing regions will face water demand exceeding supply by 50%. The Paris Declaration on Aid Effectiveness has not been effectively adopted by water sector donors.

Water in the Universe

The universe’s water is produced as a byproduct of star formation, detected in interstellar clouds and possibly existing in abundance in other galaxies. Water vapor is present in: Atmosphere of the Sun, Atmosphere of Mercury (3.8 ppm), Earth’s atmosphere.

Water Habitability

Liquid water is essential for life on Earth as it maintains a stable temperature and supports various forms of life. The Gaia hypothesis proposes dynamic processes governing Earth’s temperature via greenhouse gases and albedo.

The Value of Water

Water is considered a purifier in most religions, including Christianity, Hinduism, Islam, Judaism, Rastafari movement, Shinto, Taoism, and Wicca. Immersion or aspersion with water is a central sacrament of Christianity called baptism and also part of other religions such as Islam (Ghusl), Judaism (mikvah) and Sikhism (Amrit Sanskar).

Water in Literature

In the modernist novel Ulysses, the ‘water hymn’ is considered one of the most remarkable passages, representing the theme of everlasting life. Water’s properties include its universality, democratic equality, vastness, and variability, as well as its healing virtues and buoyancy.

Water in Art

The Value of Water at the Cathedral of St. John the Divine in New York City featured over forty artists, including Jenny Holzer and Mark Rothko. To mark the 10th anniversary of access to water being declared a human right, WaterAid commissioned ten visual artists to show the impact of clean water on people’s lives.

Water Hoaxes

A series of hoaxes using the term ‘dihydrogen monoxide’ as a parody of scientific illiteracy began in 1983. Music by Florida-based rappers often incorporates references to water, with songs like ‘Florida Water’ and ‘H2O’ becoming hits.

Water is not just a substance; it’s a symbol of life itself. From the smallest droplet to the vast oceans, its presence shapes our world in countless ways. As we continue to face challenges related to water scarcity and pollution, understanding and valuing this precious resource has never been more crucial.