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  2. Helium - Wikipedia

    en.wikipedia.org/wiki/Helium

    Helium leaks through cracks should not be confused with gas permeation through a bulk material. While helium has documented permeation constants (thus a calculable permeation rate) through glasses, ceramics, and synthetic materials, inert gases such as helium will not permeate most bulk metals. [168]

  3. Lifting gas - Wikipedia

    en.wikipedia.org/wiki/Lifting_gas

    Methane (density 0.716 g/L at STP, average molecular mass 16.04 g/mol), the main component of natural gas, is sometimes used as a lift gas when hydrogen and helium are not available. [citation needed] It has the advantage of not leaking through balloon walls as rapidly as the smaller molecules of hydrogen and helium. Many lighter-than-air ...

  4. Chemically inert - Wikipedia

    en.wikipedia.org/wiki/Chemically_inert

    The noble gases (helium, neon, argon, krypton, xenon and radon) were previously known as 'inert gases' because of their perceived lack of participation in any chemical reactions. The reason for this is that their outermost electron shells (valence shells) are completely filled, so that they have little tendency to gain or lose electrons.

  5. Explainer-What is helium and why is it used in rockets? - AOL

    www.aol.com/news/explainer-helium-why-used...

    Helium is inert - it does not react with other substances or combust - and its atomic number is 2, making it the second lightest element after hydrogen. Rockets need to achieve specific speeds and ...

  6. Purging (gas) - Wikipedia

    en.wikipedia.org/wiki/Purging_(gas)

    The purge gas is inert, i.e. by definition [1] non-combustible, or more precisely, non-reactive. The most common purge gases commercially available in large quantities are nitrogen and carbon dioxide. Other inert gases, e.g. argon or helium may be used. Nitrogen and carbon dioxide are unsuitable purge gases in some applications, as these gases ...

  7. Combustibility and flammability - Wikipedia

    en.wikipedia.org/wiki/Combustibility_and...

    The word "inflammable" may be erroneously thought to mean "non-flammable". [3] The erroneous usage of the word "inflammable" is a significant safety hazard . Therefore, since the 1950s, efforts to put forward the use of "flammable" in place of "inflammable" were accepted by linguists, and it is now the accepted standard in American English and ...

  8. Airship - Wikipedia

    en.wikipedia.org/wiki/Airship

    The alternative lifting gas, helium gas is not flammable, but is rare and relatively expensive. Significant amounts were first discovered in the United States and for a while helium was only available for airship usage in North America. [2] Most airships built since the 1960s have used helium, though some have used hot air. [a]

  9. The world is running out of helium. Here's why doctors are ...

    www.aol.com/news/world-running-helium-heres-why...

    A global helium shortage has doctors worried about one of the natural gas’s most essential, and perhaps unexpected, uses: MRIs.. Strange as it sounds, the lighter-than-air element that gives ...