Helium is named after ‘Helios’, the Sun God, because its optical spectrum was discovered by measurements of the sun’s corona. Everyone knows that helium is used for inflating party balloons and these will float away if you let go. Incidentally there is an interesting experiments that can be done with a helium balloon inside a car: just hold it by its string, not letting it touch the roof, and watch what it does as you go around corners, brake, or accelerate.
The earliest mention of Helium in a patent appears in 1904: under the title ‘Improvements in Electric Lamps’ a small amount of helium is introduced into a mercury vapour lamp, in order to reduce the resistance.
One of the more recent applications of helium is that of the helium ion microscope, which is claimed to give better resolution than a conventional electron microscope: ‘Ion source, systems and methods’ (2007).