In this demo, a skewer is pierced through a balloon without popping it. The balloon is made from a rubber polymer. The polymer is made of many long, elastic, overlapping chains, very similar to spaghetti. When a skewer pierces the balloon, these chains are stretched and pushed open to make a hole for the skewer and the balloon does not pop. It is important to pierce the balloon near the bottom & top, where the rubber has the least amount of stress. The polymer is more able to stretch and rearrange, allowing the skewer to pass through.
When a marshmallow is placed in a large capped syringe and the plunger is pushed in, the air in the marshmallow contracts from the pressure. Conversely, if the plunger is pulled back, the pressure decreases causing the air in the marshmallow to expand.
Friday November 18, 2011: Casey and Dr. Caran presented a talk to attendees of the Virginia Association of Science Teachers’ Professional Development Institute.