Helium

Helium was first discovered - though not quite identified yet - on August 18, 1868 by French astronomer, Pierre Janssen looking at the sun during an eclipse. This was the first element identified in space before it was identified on Earth.

As many people know, helium is a hoot because it can make your voice go funny, but it is not a good idea to inhale it at the expense of oxygen. It is less well known that you can lower your voice by inhaling a dense gas such as sulfur hexafluoride. Sulfur hexafluoride is extra cool, because it is considered the world's most potent greenhouse gas.