Gray Matters by Stuart Carlson and Jerry Resler for March 22, 2021

By Archimedes Principle, a helium balloon floats upward because the weight of the balloon is less than the weight of the air it displaces. The volume of air displaced by a tanker truck remains constant regardless of whether it contains helium or a vacuum. Since helium weighs more than nothing, a truck filled with helium weighs more than a truck filled with nothing.