Balloons, both foil balloons and latex balloons, are not perfectly air-tight, so they “leak” (deflate) over time. Both latex and foil balloon has a porous material and they breathe. Air can slowly diffuse through the surface or leak through the knot.

They don’t last as long. Here are several fun facts to know:

A. Foil balloons last longer than latex balloons.
Latex is a more porous material, so air or helium escapes more quickly in latex balloons than in foil balloons.

B. Helium balloons deflate more quickly than air-filled ones.
The reason why helium balloons deflate more quickly than air-filled balloons is that helium particles are smaller than air particles, so helium particles can escape from the balloon surface more easily and causing helium balloons to deflate more quickly.

C. Balloons deflate more quickly in a hot room than in a cold one.
That is because, first of all, latex becomes more stretchy in growing heat and gases can more easily escape. Moreover, like we’ve learned from our Physics class, particles move faster in higher temperatures, which increases the escape rate of the gases. Last but not least, as the heat rises, the inner pressure of the balloon climbs up and the gases are pushed out from the inside balloon, making more balloon air leak or even explode if fully inflated.

Therefore, it is highly recommended that we don’t inflate the balloon too full, especially in the hot summer.