How Heavy Is a Balloon? Using the Ideal Gas Law

This activity makes use of the Ideal Gas Law to determine the mass of a helium-filled Mylar balloon, if it were empty. The concept of buoyancy is explored as weights are attached to the balloon to bring it to neutral buoyancy, at which point the mass of the air displaced by the balloon is equal to the mass of the empty balloon, the helium inside, and the attached weights. Out of this relationship, the mass of the empty balloon is calculated and compared to its actual empty mass.