• Question: Why is it helium balloons float?

    Asked by mollieK to Adrian, Gaia, Jim, Scott on 16 Mar 2016.
    • Photo: Adrian Buzatu

      Adrian Buzatu answered on 16 Mar 2016:

      Helium gas has a lower density than air density. That is why helium floats. Archimede’s law.

    • Photo: Scott Lawrie

      Scott Lawrie answered on 16 Mar 2016:

      Different substances have different densities. Whatever has the lowest density floats on top of high density things. Helium density is lower than normal air so it floats up. Ice is less dense than water so that’s why icebergs float in the sea 🙂

      There’s an interesting gas called Sulphur Hexaflouride which is DENSER than air so it sinks to the bottom: see this fun video! https://www.youtube.com/watch?v=1PJTq2xQiQ0

    • Photo: Gaia Andreoletti

      Gaia Andreoletti answered on 16 Mar 2016:

      As long as the weight of the helium plus the balloon fabric is lighter than the air it displaces, the balloon will float in the air 😉

Comments