Skewered Balloon

A balloon on a stick - no trick!

 

 

 

Category - Force & Motion

Key Idea - Forces In Balance

 

Purpose - This is a cool way of showing how balanced forces cancel each other.

Side view of the skewered balloon.

 

The entry zone of a skewered balloon.

 

The exit point of a skewered balloon
Nature -  Demonstration
Materials -  Balloon, wooden or metal satay skewer
Method - 
  1. Inflate balloon, but not to it's tightest possible state, and tie off.
  2. Very carefully push the skewer through the balloon at the centre of the top, at the darker spot where the rubber is thickest.
  3. Slide the skewer through until it touches the rubber at the bottom next to the knotted mouth, and push through here.
Safety - Beware the pointed stick!
Explanation - The point at the top of the balloon has the thickest rubber, especially when do fully inflated. This thick rubber pulls back against the stretching force of the inflated balloon. When the skewer goes through this point the “pull” of the thick rubber is strong enough to hold against the “pull” of the inflated balloon, so the balloon does not pop.
Notes - It works best with a really sharp skewer, so it is often worth sanding the point slightly and making sure there are not splinters along the length.

An extra trick to almost guarantee success is to push a very sharp pin through the top just before doing the demo to give you hole to aim for.