Materials Needed
- An empty plastic syringe
- several mini-marshmallows
Procedures
- Put one or two marshmallows in the barrel of the syringe.
- Cover the tip of the syringe with your finger.
- Pull the syringe back and watch what happens to the marshmallow.
- Plunge the syringe forward and watch what happens to the marshmallow.
What’s Happening?
As you pull back the plunger on the syringe, you are decreasing the air pressure in the barrel of the syringe by allowing the air molecules more space to move around in. The air in the marshmallow "pushes" out and causes it to expand. The opposite happens when you push in on the plunger. As the air pressure increases the marshmallow is compressed.
