PURPOSE: To demonstrate the force of surface tension.
DESCRIPTION: Two balloons are filled to different diameters from either the house air supply, by mouth or by a portable electric pump. Open the connecting valve. The small balloon will inflate the large balloon, and deflate itself.
This is understandable if one thinks about the force required to inflate a balloon by mouth. It is easy to inflate a balloon when it is enlarged, but it is quite difficult to blow up a balloon when it is small.
EQUIPMENT: Two balloons from general use. Either a rubber hose and a hose clamp from the valve drawer or a small valve from the glass drawer in the chemicals cabinet may be used to connect the balloons.
SETUP NOTES: Be sure to test the connection between the balloons and the hose or valve for small leaks.