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.

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Blow up balloons and put them into the nitrogen and they will contract to a very small volume. Let them warm up on the table and they will expand to their original size.  NOTE:  when the balloon is frozen in liquid nitrogen the small amount of liquid that appears in the balloon is liquid oxygen and may have a slightly bluish appearance.  It may be more visible to break the balloon and pour this liquid into a wine glass.  Instead of balloons you may also use air cushion packs that come as packing insulation. These are usually clear to make the liquid oxygen visible and they are fairly easy to tear to pour the liquid oxygen out.

The temperature of liquid nitrogen should be a -196^o C or approximately 77^o K.