Helium

Helium is a colorless, odorless, and non-toxic inert gas. It is the second lightest element in the universe, after hydrogen. Helium is used in a variety of applications including party balloons and other inflatable toys, medical imaging, welding and metal fabrication, and cryogenics. Helium is also used in a variety of other applications, such as leak detection, scuba diving, and rocketry.