HEL :p Explain how precipitation happens. Use complete sentences and give at least two supporting details.

In a general aspect, humid and warm air moves to lower latitudes or in altitude, losing heat and getting colder. Its humidity condenses and causes precipitation. Depending on the air movement there are different kinds of rain.  

Explanation:

At a global level, it occurs unequal warming of the atmosphere, which depends on many factors and varies with latitude. This occurs because solar radiation reaches the earth differently at different latitudes, resulting in big convective cells of atmospheric circulation: Hardley cell, Ferrel cell, and Polar cell.    

A convective cell is the movement of the humid air among different latitudes. Air moves from higher latitudes to lower latitudes, getting warm, getting less dense, and ascending. As the air gets higher in altitude, it´s density and pressure decrease, so the air tends to expand with elevation in response to the reduced pressure. Gases in expansion experiment adiabatic cooling, losing caloric energy as their molecules move getting farther away from each other. As the air gets higher, it gets colder, and hence, denser. The result is that descends again. Humidity gets denser and precipitates.

• Rain is controlled by temperature on the earth´s surface, atmospheric global air circulation, the position of the mountains and oceans, closure to the oceans.  

• There are different kinds of precipitations according to their origin.

i. Convective precipitation: These are the most typical ones. Air gets warmer and less dense, elevating in altitude with humidity. On the way, it starts to get colder, and the humidity condenses, resulting in precipitation. Depending o the degree of condensation, the precipitation might be in a liquid state (rain), semisolid-state (snow), or solid-state (hail).

ii. Frontal Precipitations: They occur when a polar front coming from higher latitudes collide with a warm front coming from lower latitudes, resulting in a strong rain. This is typical of grasslands or temperate forests (approximately 40 º latitude)

iii. Orographic Precipitations: They occur when humid wind ascends by a mountain range, causing its adiabatic cooling, condensing the humidity, and precipitating.  

characterization of nanoparticles is a critical step in nanomaterial production as it provides information of dimension, morphology, surface charge, distribution and degree of surface functionalization.

not sure what it is