No Pop Balloon

No Pop Balloon
Can you stick a sharp object into a balloon without it bursting? It seems like an impossible task, but once you learn the science behind the secret, you'll see that it's very possible and easy to do.

  • To demonstrate the ability of cross-linked polymers to stay together and allow the balloon to be pierced without popping.

  • Experiment Details:
    • Type: Physical change
    • Grades 3-6
    • Difficulty of Project: Easy (Level 2)
    • Cost of Completing Project: $2
    • Approximate Time: Less than 5 minutes

Step-By-Step Procedure
Blow up a balloon and stick 2-inch pieces of tape to the surface in an X.

Use the pin to puncture the balloon at the center of the cross. Even though you will be able to feel air leaking the balloon will not pop.
Watch the hold through the tape. It will spread and eventually pop over time.
Observation & Conclusion
When you puncture the balloon, it is not air rushing out of the hole that causes it to pop. Itís actually called catastrophic crack propagation. This means that it is the eventual spreading of the hole that causes the balloon to pop. The hole spreads, in effect ripping open the balloon. The tape slows down the process so that it can be seen more clearly.
Science Fair Questions
1. Would this experiment work without the tape?

2. Would this work if there was no tape but the pin was lubricated?

3. Does it matter if the balloon is inflated more or less?