Subject: What is the correct hypothesis for the egg in the bottle experiment?

I am a substitute in a 6th grade lab for the next 5 weeks. (my field 
is music)!!   The students are practicing formulating hypotheses for 
an assortment of experiments.  There is some dispute among some of 
the students as to exactly what an accurate hypothesis would be for 
the egg in the bottle experiment.  This experiment teaches the 
students about expansion and contraction of air. Could you help me 
out?

Re: What is the correct hypothesis for the egg in the bottle experiment?