Marshmallow Man in Vacuum

4E20.41

Place a marshmallow man in a vacuum chamber. There are three important behaviors to note in this demonstration. First, when the marshmallow man is in the chamber before the air has been evacuated the atmospheric pressure is trying to press the marshmallows inward, but the air inside the marshmallows is pushing outward trying to expand the marshmallows. This pressure balance allows the marshmallows to retain their shape. By evacuating the air inside the chamber, there is no longer a pressure balance from the atmosphere so the air inside the marshmallows pushing outward makes the marshmallow man expand. Since the marshmallows are mostly air and sugar, some air will escape from the marshmallows. Once the air is let back in to the chamber, the marshmallow man will deflate since there is not as much air in the marshmallow as before.