Water (H2O) is the most abundant molecule on Earth’s surface, constituting about 70% of the planet’s surface. In nature it exists in liquid, solid, and gaseous states. It is in dynamic equilibrium between the liquid and gas states at standard temperature and pressure. At room temperature, it is a nearly colourless with a hint of blue, tasteless, and odourless liquid. Many substances dissolve in water and it is commonly referred to as the universal solvent. Because of this, water in nature and in use is rarely pure and some of its properties may vary slightly from those of the pure substance. However, there are many compounds that are essentially, if not completely, insoluble in water. Water is the only common substance found naturally in all three common states of matter. Water is essential for life on Earth. Water usually makes up 55% to 78% of the human body.
Clean, fresh drinking water is essential to human and other lifeforms. Access to safe drinking water has improved steadily and substantially over the last decades in almost every part of the world.
The blue Planet…
…..Earth’s surface is 71% water but most of it is seawater
… but only 2.5% of all water is freshwater (i.e. not seawater) and about 1.5% is under polar ice caps, continental ice sheets and glaciers, according to WHO reports over 50% is already polluted.
…1.2 billion people, one out of five lacks access to safe drinking water
… more than 5 million people a year die of waterborne diseases.