Sunday, November 1, 2009

Water Cycle Evaporation, Condensation, Precipatation and Infiltration and how they are linked together.


Evaporation

Evaporation is the vaporization of a liquid and the reverse of condensation. A type of phase transition, it is the process by which molecules in a liquid state (e.g. water) spontaneously become gaseous (e.g. water vapour). Generally, evaporation can be seen by the gradual disappearance of a liquid from a substance when exposed to a significant volume of gas. Vaporization and evaporation however, are not entirely the same processes. For example, substances like caesium, francium, gallium, bromine, rubidium and mercury may vaporize, but they do not evaporate as such.

Condensation

Condensation is the change of the physical state of aggregation (or simply state) of matter from gaseous phase into liquid phase and the reverse of evaporation. When the transition happens from the gaseous phase into the solid phase directly, bypassing the liquid phase, the change is called deposition. While condensation can occur in many different substances, the condensation of water vapor in air is by far the most common experienced (such as the formation of dew on a cold drink).

Precipatation

Precipitation is the formation of a solid in a solution during a chemical reaction. When the reaction occurs, the solid formed is called the precipitate, and the liquid remaining above the solid is called the supernate. Powders derived from precipitation have also historically been known as flowers.

Infiltration

Infiltration is the process by which water on the ground surface enters the soil. Infiltration rate in soil science is a measure of the rate at which soil is able to absorb rainfall or irrigation. It is measured in inches per hour or millimeters per hour. The rate decreases as the soil becomes saturated. If the precipitation rate exceeds the infiltration rate, runoff will usually occur unless there is some physical barrier. It is related to the saturated hydraulic conductivity of the near-surface soil. The rate of infiltration can be measured using an infiltrometerr.

No comments: