posted by anne .
"Blow up a balloon and tie it up. Leave it for a few days. After a few days, the balloon becomes smaller.Why?"
The answer given is that the air particles diffuse out of the balloon.
Can you please explain the answer? I understand that diffusion involves particles moving from a region of higher concentration to a region of lower concentration.
Why are air particles able to diffuse out of the balloon?
There are gaps between the rubber molecules of a balloon that are barely large enough to let air molecules slip through. The process is slow becasue many collisions are required. It is a special case of diffusion from a dense region of air (inside the balloon) to the outside.