Explanation text in some way is similar to procedure text. Explanation passage often make description about how something happens or why the thing occures. While procedure text bring the instruction on how to make something happen completely. The following example of explanation text about how rain happen is best showing on what is explanation text, what is the purpose or social function of explanation text and how it differ from other text types. Explanation text often use technical terms related to the thing which is being explained. Explanation text is commonly compose in the mode of simple present tense.

How does Rain Happen?
Rain is the primary source of fresh water for most areas of the world, providing suitable conditions for diverse ecosystems, as well as water for hydroelectric power plants and crop irrigation.
The phenomenon of rain is actually a water circle. The concept of the water cycle involves the sun heating the Earth's surface water and causing the surface water to evaporate. The water vapor rises into the Earth's atmosphere. The water in the atmosphere cools and condenses into liquid droplets. The droplets grow until they are heavy and fall to the earth as precipitation which can be in the form of rain or snow.
However, not all rain reaches the surface. Some evaporates while falling through dry air. This is called virga, a phenomenon which is often seen in hot, dry desert regions.