Makers faire project | Science homework help

PVC Marshmallow Launcher (Science Faire Project ) 
Ingredients:
• One 1/2 inch x 7 inch PVC pipe
• Six 1/2 inch x 3 inch PVC pipes
• Two 1/2 inch PVC tees
• Two 1/2 inch PVC caps
• Two 1/2 inch PVC 90-degree elbows
• Marshmallows
Instructions:
STEP 1: Connect the PVC pipes and connectors to create the STEM Shooter in the picture below: 

STEP 2: Place a few marshmallows into the end of the STEM Shooter. 
STEP 3: Blow through the opening at the top of the STEM Shooter, forcing the marshmallows out the other end. 
Explanation: 
Newton’s First Law of Motion says an object at rest will remain at rest until acted upon by an outside force or an object in motion will continue in the same direction until acted upon by an outside force. The marshmallows will remain in the gun until your breath forces them out of the gun. Once your breath forces them out of the gun, they will remain in motion until acted upon by an outside force.