make a cloud
You can make a cloud. Well, okay, a very tiny one compared to
the ones nature makes. But you will use essentially the same
techniques that nature uses.
Put about a quarter cup of warm water into a clear plastic
soda bottle. Cap the bottle or put your hand over the opening
and shake the bottle vigorously for 5 or 10 seconds. What you
are doing is warming the air and adding moisture to it. Then
light a match and drop it into the bottle. The match should
quickly go out. That adds smoke particles to the air and is
equivalent to cloud seeding[the particles encourage water
vapor to form drops]. Then put your mouth to the bottle and
force in as much air as possible. Your breathe adds more
moisture. The increase in pressure causes a rise in temperature.
Then suddenly release the pressure within the bottle. That
causes a sudden drop in temperature. When temperature drops
the air can not hold as much moisture. Water drops form
on the smoke particles and a cloud is born. Another way to
'seed' the air in the bottle instead of using a lit match is
to drop in a pinch of chalk dust. To get the necessary rise
and fall in pressure a cork can be pushed into the bottle
and then backed out. Some wine bottle corks happen to fit the
mouth of a plastic soda bottle. A cork can be made larger by
boiling it in water. A little vegetable oil may make a tight
cork slide more easily.