With Best Regards: Closing Your Letter. June 17, 2014 by. When writing professional or informal emails and letters, it is often considered proper etiquette to complete your correspondence with an appropriate closing signature.
What two conditions are needed for clouds to form? Air must be cooled to its dew point and particles must be present in the air When are clouds formed by ice crystals instead of drops of liquid water?
Clouds form whenever and wherever there is more water in a particular volume of the atmosphere than it can hold as vapor. The point at which air holds as much water vapor as it can without liquid water forming (condensation) is called the saturation point. When air cools, the amount of water vapor it can hold decreases. The most effective cooling process in the atmosphere is lifting. As air rises, its presssure decreases, thereby allowing it to expand and cool. With sufficient cooling, the air reaches saturation and small cloud droplets begin to form.