Order early for pre-holiday delivery. Flinn will be closed December 24th, 2025,
through January 4th, 2026, reopening Monday, January 5th, 2026.
Orders received after 10:30 AM Central Time on Tuesday, December 23rd, 2025,
will ship after we return.

Publication 91851
Price: FREE
Archimedes’ principle and the density of air are difficult concepts for many students to understand. This simple demonstration uses a balloon filled with dry ice to illustrate the buoyancy of air and determine the density of air.