As you would know, a cloud is a visible aggregate of minute water or ice particles suspended in air. Clouds form when warm rising air and water vapor pools, cools, and condense. The possible reasons why this happens could be one or more of the following: (1) warming of the air at the earth's surface (convection) (2) air cooling as it expands, such as when wind encounters a mountain and moves up side (3) activity at a front or low pressure system (4) air expanding and cooling, such as when the rising air is exposed to lower pressure. However, cool air cannot support as much moisture as warm air. Therefore warm air that is rising will cool and reach a point whereby its relative humidity is 100%. It is at this point that moisture begins to condense onto the surface of particles in the atmosphere, such as tiny dust particles, soot, salt, and sulfate. These particles act as cloud condensation nuclei (CCN).
This is all the background information needed, when you begin this activity.All you need for this activity is: a clear disposable plastic 2-liter soft drink (or drinking water) bottle (remove label), A sheet of black construction paper, some hot water
The method is as follows:
Get some really hot tap water and pour 2 inches of it into the 2-liter bottle. Place your mouth over the opening and blow into it to ensure the bottle is fully expanded. Shake the bottle vigorously for one minute. This will distribute water vapours in the air.
Light a match. Let it burn for two seconds, then drop it into the bottle.( This step is preferably done with an adult around). Alternatively, you can use an incense stick (Agarbatti). To get a thick cloud formation It is necessary that sufficient smoke from the extinguished match stick enters the bottle. Quickly recap the bottle.
Press hard on the bottle for ten seconds. The bottle is strong, so push really hard. Release, observe, if you can not see any difference inside the bottle, press the bottle again and release, keep on repeating this step till you see a cloud inside the bottle.
When the cloud has formed, quickly unscrew the cap. You should see the cloud escape from the bottle. If not, give the bottle a light squeeze.