Concepts of Physics

IIT JEE Physics (1978-2018: 41 Years) Topic-wise Complete Solutions

Burst a Balloon

Objective

To visualize that pressure plays a key role in rupturing a balloon and not the force.

Introduction

If an inflated balloon is taken in hand and continuously squeezed, it ruptures at a certain moment. It happens when the pressure becomes high and tension in the rubber goes beyond the breaking strength. The rupturing is decided by the pressure and not by the force.

Apparatus

few balloons, a wooden board to sit/stand

Procedure

Take three balloons. Inflate them partially. Now place a wooden board or inverted stool on these balloons. Call a volunteer and tell him to carefully stand on the board. Most likely, the balloons will not burst. Even if the volunteer makes little movement, the balloons do not burst.

Discussion

The weight of the standing person is distributed over the flattened area of the balloons in contact with the board. The pressure on the balloons is thus reduced and save them from bursting. The pressure estimation can convince that it is approximately equal to the pressure when balloon is pressed with a finger with few newton of force.