Editing Egg In A Bottle (section)

== Why This Works ==

''Pressure'' is when a force is applied over an area. ''Air Pressure'' is the pressure that the air around us applies. The amount of air pressure we feel depends on three things: how much '''mass''' the air has, how much '''energy''' it has, and how much '''space''' there is for the air. We can see these affects with any of the three methods for this demonstration.

When we have the paper or the candles burning in the Erlenmeyer flask, they are heating up the air and giving it '''more energy'''. This increase in energy causes the air to try to take up '''more space''', which is why we hear the air squeezing out past the egg or water balloon. Even though there is '''less mass''' in the flask, the air inside has enough energy to push back against the air outside. This is why the balloon that is stretched over the top will "inflate" while the paper is burning inside. Once the paper or the candles goes out, however, then the air inside starts to '''lose energy'''. This means the air will take up '''less space''', and there will be some empty space inside the flask. This empty space is called a ''Vacuum'', and the air outside the bottle will try to push '''more mass''' into the vacuum. This is because the air inside the flask has ''low'' air pressure, and the air outside has ''high'' air pressure. The outside air will push the egg or water balloon into the flask, or cause the balloon stretched over the top to "inflate" into the flask!