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I tried to make rain with a bottle and a balloon but it failed.

The bottle was small, only a couple inches wide and the threaded part that I had the balloon on was less than an inch. In particular it was the size of this hydrogen peroxide bottle:

enter image description here

It was originally a hydrogen peroxide bottle but all the hydrogen peroxide was out of it when I did this experiment. I stretched the balloon a little bit and put it over the threaded part of the bottle. But right before that I put hot water in the bottle. I knew that some water was evaporating. Also there was regular air(including dust particles) inside the balloon(I did this outside during a dry spell during the summer). This gives plenty of opportunities for the water to condense to form a cloud in the balloon and eventually, rain.

However I left it out there for several days and nothing happened. The balloon didn't inflate from the water vapor bouncing off of the balloon. The water didn't condense enough to be noticeable. Rain didn't form. I thought that maybe there was too little water and too little air so I went to a much bigger bottle(about a gallon in size). The balloon started to separate. I also had a control of an open bottle in the same conditions while doing this experiment. The water level did not change in the open bottle even when the humidity was low.

So why didn't the balloon inflate if the fact that both the water and the air were hot should have increased the vapor pressure, thus causing the balloon to inflate?

Why didn't the water condense into a cloud that I could see through the latex of the balloon if it were inflated?

Why didn't the water get to the critical size for raindrops if there were plenty of dust particles in there for the water to condense on to form water droplets and eventually raindrops?

Why didn't the water level in the open bottle change?

Is there anything I can do to improve this rain in a balloon experiment besides having a source of heat underneath the water?

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    $\begingroup$ You have to read up on the phase diagram of water en.wikipedia.org/wiki/Water_%28data_page%29#Phase_diagram and on condensation en.wikipedia.org/wiki/Condensation . And keep in mind that at the same temperature the exchange of water molecules with air is a two way process. No inflation can happen. $\endgroup$
    – anna v
    Commented Jan 16, 2016 at 4:13
  • $\begingroup$ But I saw an experiment years ago that used hot water to inflate a balloon and eventually make rain. This is what I based my experiment off of. And I know that water evaporates at all temperatures, even ice cold or below. This is how come water doesn't have to be at 212 to evaporate at 1 atm. Evaporation can happen at any temperature, steam only starts forming at 180 degrees F, otherwise it is considered water vapor. And with the vapor pressure increased by temperature increase in both the water and the air the equilibrium should be more towards gas and thus inflation. $\endgroup$
    – Caters
    Commented Jan 16, 2016 at 4:18
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    $\begingroup$ If you heat the bottle , then the water evaporates faster than it condenses. If then you cool the balloon , looking at the phase diagram, below the vapor state , then condensation will happen. At equal temperatures everything is in equilibrium. $\endgroup$
    – anna v
    Commented Jan 16, 2016 at 4:21
  • $\begingroup$ Not having seen the demonstration done, I'm unclear on exactly what you expect, but anna is certainly right that you need to establish areas of different conditions. The demonstration is likely a delicate trick that depends on have the right range of water temperature, enough water, a large enough balloon in a cool enough room, and a way to insure that a significant amount of moist air crosses from one region to another. I would very much like to hear if and how you succeed, because I could use a demonstration of this order in one of my classes. $\endgroup$
    – dmckee --- ex-moderator kitten
    Commented Jan 16, 2016 at 17:38

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