It’s not magic, kiddo. It’s science!
Sulfur hexafluoride (SF6) is a colorless, odorless gas that is more dense than air at 6.12 g/L (at sea level). This density is why you can pour it into a glass container and float a light-weight aluminum “boat” on its gas “sea.” Watch this demonstration at the Physikshow of the University of Bonn!
via Quora.
