Why do balloons deflate over time?



Why do balloons deflate over time?

In: Chemistry

Gas molecules are small and rubber, particularly thin rubber like that used for balloons, is very slightly porous. Because the pressure inside is greater than the outside air, molecules will diffuse through.The rate of diffusion is governed by

1) the size of the molecule so something like helium which is just single atoms and therefore tiny will escape quicker than molecules like nitrogen consisting of two atoms per molecule.

2) the porosity of the skin so a Mylar balloon, and particularly one with a metal coating, will deflate more slowly.

Rubber is slightly leaky. Air/helium molecules slowly squeeze through the rubber over time, exiting the higher pressure balloon interior and deflating it.

Because a balloon is not a perfectly sealed or impermeable material. There are microscopic holes in the stretched material through which air continues to seep through, while the knot tied at the bottom also isn’t completely sealed, leaking air over time

Though the Reason part has already be answered, I wanna address the prevention part.

There are these Creams being sold in the market, which when applied on the surface of the balloons, helps prevent the leakage to a large extent. It is mostly used on the Helium filled balloons to keep them airborne for longer period of time.

One call also apply grease or some type of oil with some specific properties, so that the weight of the Balloon does not exceed a certain ratio.

Everything got holes in it. Make a lead box and put a light in it. Measure around the box with a light detector. You’ll find some little specks of light managed to fly out.