Two elements – gases- that are lighter than air. However, I urge you to keep your lighter away from the Hydrogen unless you have this passion for large explosions.
Helium = Happy Birthday!
Hydrogen = Bon Voyage!
The reason I’m even thinking about this is that I recently saw an article stating that there is a shortage of Helium. There is such a dearth of Helium that a number of “Party Stores” are closing their doors. They are unable to inflate enough of those festive Helium Balloons to keep their customers and all of those Birthday Cake Sugar wired two year olds happy.
Unhappy Customers = Job Hunting