Abstract: The apparatus has a transparent casing and an oblong toroidal shape in the form of a bucket elevator. First and second vertical compartments are separated by a partition and a clear cylindrical passage is formed around the circumference of the apparatus. First and a second sheaves are mounted above one another along the partition. A flexible loop is mounted around the sheaves and a series of balloons attached to the flexible loop at spaced intervals. The first compartment is opened to ambient air. The lower region is filled with argon gas and the second compartment is filled with helium gas. The balloons are filled with the helium gas such that the balloons have buoyancy in the first compartment and heaviness in the second compartment, and the pool of argon gas impedes the diffusion of ambient air in the second compartment.

Abstract: The apparatus has a transparent casing and an oblong toroidal shape in the form of a bucket elevator. First and second vertical compartments are separated by a partition and a clear cylindrical passage is formed around the circumference of the apparatus. First and a second sheaves are mounted above one another along the partition. A flexible loop is mounted around the sheaves and a series of balloons attached to the flexible loop at spaced intervals. The first compartment is opened to ambient air. The lower region is filled with argon gas and the second compartment is filled with helium gas. The balloons are filled with the helium gas such that the balloons have buoyancy in the first compartment and heaviness in the second compartment, and the pool of argon gas impedes the diffusion of ambient air in the second compartment.