Science Questions

Does internal gas affect your weight?

What volume of gas does a person has to have to affect their own weight. Does having gas make you weigh more or less? Sandra

Diana -   Well we have had a bit of a discussion about this and I think what it comes down to is what your farts are composed of.  Of course, there is some hydrogen sulphide in there and occasionally some methane.  I think it depends what kind of bacteria you have in your gut but I think it was about five out of seven people will have methane produced in their farts.  And of course, methane is lighter than general gas (air) and therefore, younwould think if you have that in your gut, then it would make you a bit lighter.  But of course, there’s a question of pressure.  So, if you have a lot of gas in your body that’s under pressure, it would actually be denser than air and actually make you heavier.  What do you think Dave?

Dave -   Yeah.  The very things which could be in the gas, one which could really make the constituent is hydrogen which is one of the lightest gases we know of and that can be up to 50% of your flatulence and so if it’s made mostly of hydrogen then it’s going to be much less dense and the pressure change is going to be very, very small. So when you expel the gas, it could even make you heavier because the hydrogen could’ve been acting a bit like a helium balloon in floating you ever so slightly.

Diana -   I don't know if you could do a test by seeing if that gives a squeaky pop with a lighted splint?

Chris -   Maybe Kitchen Science for the future.

January 2010