Disclaimer:

Reprinted by permission of Dick Berg, University of Maryland, for use on this website.

The demonstrations contained and referenced herein are listed for the purposes of cataloging and describing physics demonstrations which should be conducted only under the direction of a trained instructional support professional or physicist. These demonstrations are not presented for the purpose of being conducted by persons unconnected to this Facility and/or persons not consulting with or being supervised by the recognized instructional support professional or physicist and his/her staff. The University is responsible only for those demonstrations carried out using its own equipment using established safety and scheduling policies, and bears no responsibility for those choosing to use this source material for their own purposes. All demonstrations described and contained herein are public domain, and can also be found in reference materials in libraries, bookstores, and electronic sources.

Further information regarding legal liability in use of demonstrations and labs will be found on the web site Injuries in School/College Laboratories in USA.

The University of Iowa Disclaimers:  University of Iowa Disclaimer All Rights Reserved..

Blow up the helium balloon to a small size and attach to the Tygon tube assembly that is closed off with the hemostat.  Take another helium balloon and blow it to a larger size and attach to the other end.  When the hemostat is removed the small balloon should blow up the large balloon.

Attach one of the balloons over the rubber stopper, blow it up to a small size, and close off the stopcock.  Attach another balloon over the other rubber stopper, blow it to a larger size, and close off the stopcock.  Attach the two assemblies together with the included tubing and open the stopcocks.  

For the balloon part of this demonstration to work well the volume of the larger balloon should be at least half of the balloons full size.  The volume of the smaller balloon should be very much less that the larger balloon so that the rubber is not stretched very much.  Should you blow the balloons to very close to the same size the demonstration will take a very long time and the probability is that the balloons will come to an equal size.