Water

Water is the most common substance on the earth. The natural sources of water are rain, rivers, lakes, springs, sea, wells, etc. Rainwater is regarded as one of the purest forms of naturally occurring water. Rain is produced by the condensation of the water vapour present in the air. Nearly one-third of the rainwater sweeps into the ground through soft and loose strata of sand, gravel and chalk and then reaches some impermeable stratum of clay and slate. It remains trapped in this layer and tries to escape out through the small cracks of rocks which we call spring. The water in the well is one example of trapped water below the ground. Water from wells has been used from time immemorial for drinking and irrigational purposes.

Physical properties of water

• Pure water is colourless, tasteless and has no smell.
• Water can be found in three state solid, liquid and gas.
• Water is transparent.
• Melting and boiling point of water is 0^oc and 100^oC respectively.
• Water has no definite shape.
• Water retains heat, so its temperature falls slowly.

Chemical properties of water

• Water is formed from two atoms of hydrogen and one atom of oxygen (H2O).
• Water is neutral. It has neither basic or nor acidic properties.
• Temperatures of 212°F (or 100°C) are required to break the hydrogen bonds and convert liquid water into water vapor.