Some of the most dramatic changes effected by water are accomplished by processes too minute to be seen with the unaided eye. A drop of rain may pound the soil with a force of 2.3 pounds per square inch or 16 kpa (in a average downpour, some five million drops fall on every acer [0.4ha] every second). A crystal of ice lodged in a rock pore, formed as moisture is frozen, expands with a pressure of 400 pounds per square inch (2,76- kpa );
Multiplied by many crystals, this is enough to split the rock.
Multiplied by many crystals, this is enough to split the rock.
A crystal of salt left behind by evaporating water grows in crevices of rock, expanding unit the rock is fractured. Water also exerts a profound chemical force on the earth. Certain elements abundant in groundwater, rain and dew on minerals in rock, dissolving it into the soil, and in some cases creating plant foods.
If water can destroy rock in many ways, it can also rebuild it. Three fourths of the surface of the earth is now covered with layer of sedimentary rock, which are built out of compressed material washed away from one place and re-deposited in another.
This details was collected from the Book WATER.
Published by life science library.
By
Santhosh.
