What is water?

Water is a chemical substance composed of two hydrogen atoms bonded to one oxygen atom, represented by the chemical formula H₂O. It is a vital compound for all known forms of life and is the most abundant substance on Earth. Water exists in three states: liquid, solid (ice), and gas (water vapor), and it plays a crucial role in various physical and biological processes. Key properties of water include: 1. **Polarity**: Water is a polar molecule, which means it has a slight positive charge on one end (the hydrogen atoms) and a slight negative charge on the other end (the oxygen atom). This property allows water to form hydrogen bonds, leading to high cohesion (attraction between water molecules) and adhesion (attraction between water and other substances). 2. **High Specific Heat**: Water can absorb a lot of heat before its temperature changes significantly, making it an excellent temperature buffer for the environment and organisms. 3. **Solvent Properties**: Water is often called the "universal solvent" because it can dissolve many substances, including salts, sugars, acids, and gases. This property is essential for chemical reactions in biological systems. 4. **Density Anomaly**: Water is less dense as a solid (ice) than as a liquid, which is why ice floats on water. This property is crucial for aquatic ecosystems, as it insulates the water below and helps maintain a stable environment for organisms in colder climates. 5. **Surface Tension**: Water's cohesion leads to a high surface tension, allowing some insects to walk on its surface and enabling water droplets to form. Water is critical for hydration, agriculture, industry, and various ecological processes, making its availability and quality essential for health, economies, and ecosystems.