The Hypothesis of 10th grade students from The Clermont School was obtained after studying all the hypothesis the students gave, and developing a general one:

The main factor that may affect the boiling point of the water is the atmospheric pressure which depends on the elevation. At lower places the atmospheric pressure is higher so the water that is boiling has to brake a higher atmospheric resistance. This is why it takes the matter more time to change from liquid to gas. In higher places the resistance is lower so the time to break it is less.