Helium is used for applications ranging from sending rockets into space to helping deep sea divers breathe. Helium is also at work in the balloons at parties or in the blimp floating overhead at a ball game. It is also used as a coolant in nuclear reactors, the Large Hadron Collider, satellite instruments and MRI scanners.
As an inert gas with low density, helium is used to fill decorative balloons, weather balloons or airships so that they float. It's mixed with oxygen to make breathing easier for deep-sea divers or others working in pressurized conditions, and was also used to cool the liquid oxygen and hydrogen that powered the Apollo space vehicles. In addition, many supermarkets use a helium-neon gas laser as a bar code scanner.
In 1868, the scientist Pierre J. C. Janssen was the first to notice helium as a yellow line in the solar spectrum when observing a solar eclipse, but it wasn't until 1895 that the atomic weight of helium was discovered and the element named. Janssen, along with fellow scientist Norman Lockyear, determined that helium, from the Greek word "helios" meaning "sun," was the most appropriate name. Since that discovery, humans have used helium for many different applications, both for furthering scientific discovery and for entertainment.