All magnets have north and south poles. Opposite poles are attracted to each other, while the same poles repel each other. When you rub a piece of iron along a magnet, the north-seeking poles of the atoms in the iron line up in the same direction. The force generated by the aligned atoms creates a magnetic field.
Calderas are what sometimes surround it
Unclear/incomplete question. However, I inferred you need an explanation of the phenomenon of rainfall.
<u>Explanation</u>:
Basically, the phenomenon of rainfall follows a natural cycle called the water cycle. What we call <em>'rainfall'</em> occurs when water condensed (in liquid form) in the atmosphere is made to fall down on the ground as tiny droplets as a result of the forces of gravity.
<u>The water cycle makes rainfall possible:</u>
- First, water on the earth's surface is evaporated (or is absorbed into) the atmosphere.
- Next, it then condensed into liquid form; which later falls to the surface to the ground again. And the process continues.