• Question: Why do balloons float when they are filled with helium

    Asked by here520yoga on 11 Mar 2025.
    • Photo: Zoe Vance

      Zoe Vance answered on 11 Mar 2025:

      Helium is lighter than air (air is mostly nitrogen) so a helium balloon rises above the air. If you were to put a helium balloon in a gas that’s lighter than helium, like hydrogen, then you would see it sink!

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