• Question: why does are farts smell?

    Asked by olliep to Adam, Catherine, Karen, Leila, Nazim on 12 Mar 2012.
    • Photo: Adam Stevens

      Adam Stevens answered on 12 Mar 2012:

      Mostly it’s ammonium sulphate, which is what gives rotten eggs their smell too.

      A lot of people think the smell is methane, but methane doesn’t smell of anything, and actually most people don’t even fart it out!

    • Photo: Leila Battison

      Leila Battison answered on 12 Mar 2012:

      Most of our farts are made up of nitrogen, which is what makes up most of the air too. The smell comes from sulphur compounds, that are made by the bacteria that live in out stomach and intestines.

      Farts and poo of carnivores (who eat meat) are much much much smellier than herbivores (who only eat plants). This is because they have different bacteria in their stomachs, who break down different things, and give off different gases.

      We have geese and peacocks at home, and you can always tell the difference between their poo because the geese only eat grass, so it is green and wet, and the peacocks eat flies and insects, so their poo is brown, smelly and quite solid. So now you can identify wild animals from their poo!

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