Water
From ArticleWorld
Water is a substance that is essential to all forms of life; it is colorless, odorless and tasteless. Water is the most universal solvent and the most abundant substance on Earth.
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Location
Water is found in a wide range of places and forms; although it mostly appears in oceans and polar ice caps. It is also found in clouds, river, rainwater, aquifers and sea ice. It continually evaporates, precipitates and then runs off into the sea.
Water precipitates varying by region; rain is common in most, but hail, snow, fog and dew occur depending on temperature and other atmospheric conditions.
Definitions
- Potable water is water that may be consumed by humans. In some places, this resource is becoming a serious economic concern.
- The water cycle is the process of evaporation, precipitation and runoff, where water continuously flows from one from to another.
- A rainbow occurs when water drops in the air refract sunlight.
Importance in history
Rivers and irrigation have historically supplied the water that is needed for agriculture; while rivers and seas provide the opportunity for travel and commerce by ship. Erosion and runoffs play a part in the creation of valleys and deltas – two things that allow for rich soil and level ground – allowing for the establishment of cities.
Uses of water
All life forms depend on water for survival. In this sense, it is an important part of the metabolic process in the human body and it is used in the digestion of food.
Water makes up a great deal of the human body: 72 percent of the fat-free portion of the human body is made of water. The body, for proper functioning and to avoid dehydration, requires 1-7 liters of water a day. The precise count depends on the level of activity.
Health
Although the exact amount of water that is needed for healthy people is unknown. People with kidney problems should regulate their consumption, however for those without kidney problems it is nearly impossible to consume too much water, especially when it is humid or when they are exercising. It is, however, dangerous to drink too little. The recommended daily intake of water is 2.7 liters for women (including water from food sources) and 3.7 liters for men.
Water is lost from the body via urine and feces, sweating and water vapor through sweat.
Water for human consumption should not contain much salt or other impurities (common ones include chemicals or harmful bacteria).