 
The second most abundant element in the universe, helium is scarce on Earth. With atomic number 2, helium is the simplest element after hydrogen. Helium is at the top of the noble gas group (which also contains neon, argon, krypton, xenon, and radon) and is the least reactive element; it does not react with any other elements or ions, so there are no helium-bearing minerals in nature. A product of stellar nuclear fusion or radioactive decay, it is colourless and odourless.
Helium was first observed by studying the Sun. Helium is called a 'monatomic gas' since it exits as single helium atoms. It is found under the Earth’s crust with other gases; commercial helium can be extracted from natural gas. The U.S., Qatar and Algeria have the world’s major helium reserves, but these sources are being rapidly depleted. 
While most people are familiar with helium’s buoyancy, which makes it ideal for filling birthday balloons and blimps, helium has many other very important uses:
Inhaling helium makes your voice sound high and squeaky. The human voice is made up of many different frequencies mixed together; usually the sound waves your vocal cords produce travel through air in your larynx. But when they go through helium that you’ve inhaled, they travel about three times faster. That’s because helium is so much lighter than air. When sound waves speed up but their frequency stays the same, each wave stretches out. The longer wavelengths don't fit in the larynx, so don't get amplified. The higher tones, however, are stretched out so they're the perfect size to be amplified. Those get boosted, resulting in a high-pitched voice. Whatever its uses, once helium is released in the atmosphere it will continue rising until it escapes into space, making it the only truly unrecoverable element. |