Water is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth’s hydrosphere and the fluids of most living organisms. It is vital for all known forms of life, even though it provides no calories or organic nutrients. Its chemical formula is H2O, meaning that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. Water is the name of the liquid state of H2O at standard ambient temperature and pressure. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds are formed from suspended droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor. Water moves continually through the water cycle of evaporation, transpiration (evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea.
Water covers 71% of the Earth’s surface, mostly in seas and oceans. Small portions of water occur as groundwater (1.7%), in the glaciers and the ice caps of Antarctica and Greenland (1.7), and in the air as vapor, clouds (formed of ice and liquid water suspended in air), and precipitation (0.001%).
Water plays an important role in the world economy. Approximately 70% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies is a major source of food for many parts of the world. Much of long-distance trade of commodities (such as oil and natural gas) and manufactured products is transported by boats through seas, rivers, lakes, and canals. Large quantities of water, ice, and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a wide variety of substances both mineral and organic; as such it is widely used in industrial processes, and in cooking and washing. Water, ice and snow are also central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, surfing, sport fishing, diving, ice skating and skiing.
10 ways to save water at home.
- Turn off the tap when you brush your teeth – this can save 6 litres of water per minute.
- Place a cistern displacement device in your toilet cistern to reduce the volume of water used in each flush. You can get one of these from your water provider.
- Take a shorter shower. Showers can use anything between 6 and 45 litres per minute. Consider getting an aerated shower head, which combines water and air, or inserting a regulator in your shower, which puts an upper limit on flow rates.
- Always use full loads in your washing machine and dishwasher – this cuts out unnecessary washes in between.
- Fix a dripping tap. A dripping tap can waste 15 litres of water a day, or 5,500 litres of water a year.
- Install a water butt to your drainpipe and use it to water your plants, clean your car and wash your windows. A water butt can collect around 5,000 litres a year.
- Water your garden with a watering can rather than a hosepipe. A hosepipe can use as much as 1,000 litres of water an hour. Mulching your plants (with bark chippings, heavy compost or straw) and watering in the early morning and late afternoon will reduce evaporation and also save water.
- Fill a jug with tap water and place this in your fridge. This will mean you do not have to leave the cold tap running for the water to run cold before you fill your glass.
- Install a water meter. When you’re paying your utility provider for exactly how much water you use, laid out in an itemised bill, there’s an incentive to waste less of the stuff.
- Invest in water-efficient goods when you need to replace household products. You can now get water-efficient showerheads, taps, toilets, washing machines, dishwashers and many other water-saving products. For more information visit the Waterwise website.