Clouds are water, though they certainly don’t look like it from down here on the earth. But they form when water on the earth’s surface evaporates (water turns from liquid to gas – from the ocean, from a lake, river, etc.). The air with this water vapor in it rises and as it gets to very high altitude the air is cooler and the vapor starts to change back to liquid. This process is called condensation. With massive amounts of small water drops gathered close together a cloud forms and becomes visible to the eye.
With the correct temperature and some other particles for the small drops of water to hold onto, a cloud can form. In fact, small particles of dust or pollution are one of the necessary factors for cloud formation.
One comparison that is sometimes made is being able to see our breath on a cold or cool day. This happens because the air we breathe out has moisture in it. It is warm, like the air with water vapor in it that rises from a lake or the ocean. Our warm breath comes in contact with cooler air the moisture starts to return to the liquid state. In a way, we are forming clouds when we exhale. This is the same process that creates clouds when a warm front or mass of air meets a cold mass of air.
Most people learn about different types of clouds during their childhood education. Different types of clouds form various shapes due to the unique conditions in the atmosphere. There are three major kinds of cloud – cirrus, stratus and cumulus. However, scientists who study weather conditions have also identified combinations of these three types.
Cirrus clouds are generally considered to be those that appear lighter and have curled shapes. Some people use the traditional slang word “wispy” to describe them. They most often form at the higher altitudes and contain crystals of ice that form because the temperatures are lower at the high altitude.
A stratus cloud generally forms in layers and appears to be spread across the sky. They form much lower than cirrus clouds and even seem to be very close to the earth. When the clouds come all the way to the ground, we call it fog. This happens under certain unique conditions.
Cumulus clouds are the clouds that children often find shapes and animals in. They seem to pile up and have a puffed appearance. However, the bottom of a cumulus cloud is most often rather flat due to the layers of air at different temperatures and density.
Each type of cloud can be part of a weather-prediction process, with cumulus clouds pointing to clear weather in the future. Stratus and cirrus clouds might indicate unsettled weather or storms.
Scientists called meteorologists and science teachers have developed various experiments in laboratories and classrooms that show how clouds form. Each experiment must have the necessary ingredients of moisture, moist air, changing temperature etc. for the experiment to work.