Ask A Scientist Chemistry Archive

Question:
Why does a balloon filled with Helium shrink faster than a baloon that I
blew up with my mouth? My name is Randall.  I am in 3rd grade.
 
Answer 1:
Good question, Randall.  You see, balloons are made of rubber and
are porous...which means there are real tiny holes all over the
surface...holes so small you can't see them.  When you blow up a
balloon with your mouth, you're putting oxygen and carbon dioxide into
it.  These are big molecules compared to tiny old helium.  Helium can
escape through those holes in the balloon fairly easily while oxygen
and carbon dioxide can't.  So the balloon will lose helium a lot faster
than it will the air from your mouth.
-Joe Schultz
 
Answer 2:
What an awesome question!
I'm very impressed by Randall's keen powers of observation.
Nice answer there Joe.
topper