The result of making Fog in a Bottle

When my partner and I started doing the experiment we first thought it was going to be fun. We thought that the fog was not going to form in the bottle that has cold water and that the fog will only form in the bottle that has hot water. When we started the experiment we thought it was not going to work but after 5 minutes the fog started to form in the bottle that had only hot water. By the end of the experiment the fog had only form in the hot water but not in the cold water.