Is Air There?

Air is there, this can even be proven by a simple experiment. I had the chance to try this easy and very interesting experiment. The experiment is a jar with a plastic bag over it and a rubber band holding the bag to the jar. When you press the bag down it resists because the air pressure inside is increasing as stated by Boyle's law. Boyle's law is pretty much when pressure increases the density of the gas increases. Air is a gas and your hand in this activity is the pressure. Because air is there you are not able to press the plastic bag in without pushing the air out of the jar, pushing air out is only possible because the the jar and bag are not air tight.