Water is a substance composed of the chemical elements hydrogen and oxygen. It is a tiny molecule consisting of two hydrogen atoms and one oxygen atom (H2O) . Water occurs in gaseous, liquid, and solid states. It is a tasteless, odorless, and almost colorless liquid at ambient temperature and pressure. Water is the most abundant substance on Earth and is essential to life. It is the liquid that makes life on Earth possible. Water molecules cling to each other because of a force called hydrogen bonding, which is why water can do amazing things. Water is a shape-shifter and exists in three states on Earth: liquid, gas, and solid. The physical and chemical properties of water are very important for the survival of ecosystems. Some of the key characteristics of water include:
- The density of water is about 1 gram per milliliter.
- Water has the highest specific heat of any liquid (4,180 J/(K kg)), although it varies with temperature.
- Water is the most cohesive among the non-metallic liquids.
- Water molecules are also adhesive in that they stick to other surfaces.
Water is found in oceans, rivers, lakes, and underground. It is also a vital component of the atmosphere, where it exists as water vapor. Water is used for a variety of purposes, including transportation, recreation, cleaning, and generating hydroelectric power.
