Water Facts



  • Water is the only substance on Earth which is commonly found as a solid, a liquid and a gas.
  • Over 70 percent of the Earth’s surface is covered in water.
  • Water is fundamental (basic) to all life – 70 percent of our bodies is water.
  • Earth is the only planet in the Solar System to have liquid water on its surface.
  • Neptune has a deep ocean of ionized water beneath its icy surface of helium and hydrogen.
  • Dried-up river beds show that Mars probably once had water on its surface. There may be ice or water underground.
  • Jupiter’s moon Europa may have oceans of water beneath its icy surface, and it is a major target in the search for life in the Solar System.
  • In 1998 a space probe found signs of frozen water on the Moon, but they proved false.
  • Water is a compound of the elements hydrogen and oxygen, with the chemical formula H20.
  • Water is the only substance less dense (heavy) as a solid than as a liquid, which is why ice floats.
  • Water is the only substance that is solid, liquid and gas within the natural range of Earth temperatures. It melts at 0°C and boils at 100°C.
  • Water is at its densest at 4°C.
  • Ice is much less dense than water, which is why ice forms on the surface of ponds and why icebergs float.
  • Water is one of the few substances that expands as it freezes, which is why pipes burst during cold winter weather.
  • Water has a unique capacity for making mild solutions with other substances.
  • Water is a compound made of two hydrogen atoms and one oxygen atom. It has the chemical formula H20.
  • A water molecule is shaped like a flattened V, with the two hydrogen atoms on each tip
  • A water molecule is said to be polar because the oxygen end is more negatively charged electrically.
  • Similar substances such as ammonia (NH3) are gases to below 0°C.
  • Water stays liquid until 100°C because pairs of its polar molecules make strong bonds, as the positively charged end of one molecule is drawn to the negatively charged end of another.
  • Your body is mainly made of water – more than 60%.
  • You can survive weeks without food, but no more than a few days without water.
  • You gain water by drinking and eating, and as a by-product of cell activity.
  • You lose water by sweating and breathing, and in your urine and feces.
  • The average person takes in 2.2 liters of water a day – 1.4 liters in drink and 0.8 liters in food. Body cells add 0.3 liters, bringing the total water intake to 2.5 liters.
  • The average person loses 1.5 liters of water every day in urine, 0.5 liters in sweat, 0.3 liters as vapor in the breath, and 0.2 liters in feces.
  • The water balance in the body is controlled mainly by the kidneys and adrenal glands.
  • The amount of water the kidneys let out as urine depends on the amount of salt there is in the blood.
  • If you drink a lot, the saltiness of the blood is diluted (watered down). To restore the balance, the kidneys let out a lot of water as urine.
  • If you drink little or sweat a lot, the blood becomes more salty, so the kidneys restore the balance by holding on to more water.