This document presents summaries of 3 experiments on the properties of air conducted by students at Sant Josep school in Barcelona, Spain. The first experiment shows that hot air expands and cold air contracts by placing a balloon-topped bottle in hot and cold water. The second experiment demonstrates that air takes up space by trying to submerge a ping pong ball in a jar with and without tissues. The third experiment illustrates that air pressure can crush an empty soda can by boiling water inside the sealed can and then quickly submerging it in cold water.