Question

How does precipitation occur and what determines the type of precipitation that falls on earth?

Answer 1

Hint: 70% of our earth is covered with water. Even the atmosphere that surrounds our planet has water vapour. Precipitation, condensation and evaporation are the three processes that form the water cycle and maintain the level of water on earth.

Complete answer: Precipitation is the process in which water from the atmosphere falls back on earth in liquid or frozen form.
Precipitation can occur in the form of rain, sleet and snow.
-Water in the oceans, seas, rivers and other water bodies evaporate due to heat of the sun. This water vapour on reaching higher altitudes forms clouds. Precipitation happens in clouds when water vapour condenses into bigger droplets. These droplets fall down on earth when they become too heavy.
-Colder clouds, like the kind found in hilly higher altitudes, results in frozen water droplets and this leads to snowfall. Therefore it depends on the temperature of the cloud and temperature on earth’s surface if the precipitation is going to be snow, rain or hail.
Dust in the atmosphere is important for precipitation as they provide a surface for water vapour to condense.

Note: Though precipitation is always fresh water, as salt does not get evaporated, there are some cases of acid rain. Acid rain is precipitation which has acidic components like sulfuric and nitric acid due to pollutants in the air. Acid rain is harmful for the ecosystem.