Balloons are a very popular gift amongst people all over the world. There are many different reasons someone might give a balloon to a friend, family member or colleague. Many people give balloons to congratulate someone, say happy birthday or get well soon, and though so many are given as gifts, they do not last forever. Unfortunately, all balloons deflate and the rate at which it deflates is determined by a few different factors. Here is an overview of how Helium escapes from a balloon, causing it to deflate.
Latex balloons are made out of natural rubber. When rubber is formed into a latex balloon, the walls of the balloon have small microscopic pores or holes in them. These holes cannot be seen by the human eye, but they are about 1000 times larger than Helium atoms. Since these holes are so much larger than Helium atoms, the Helium atoms can easily escape from the inside of the balloon. The Helium atoms will continue to escape until there is no longer enough Helium inside the balloon to keep it afloat.
When a rubber balloon is filled with Helium, it typically retains buoyancy for only a few days. Balloons filled with air usually hold their size and shape for much longer because air particles are larger than Helium particles, therefore causing them to escape more slowly than the Helium particles. This process is scientifically referred to as diffusion, which is defined as the process by which a substance or solute migrates from a region of high concentration, through a barrier or membrane, to a region of lower concentration.
The material a balloon is made from such as latex or foil, affects the length of time a balloon remains floating by how porous the material is. The more porous the material a balloon is made from, the quicker the Helium or air particles will escape from it. Foil balloons, though they are porous, are not as porous as latex balloons, so they deflate at a slower rate. A second factor that affects the float time of a balloon, is that the inside of the balloon is treated with a special gel that allows the balloon to hold Helium or air particles for a longer period of time. Lastly, the temperature of the room the balloon is in also affects the rate at which Helium or air particles can escape. In a cold room the particles contract and become smaller, and escape from the balloon at a faster rate. In a hot room, the particles are moving rapidly inside the balloon, and escape at a much faster rate. If the room is extremely hot, the particles can expand to the point of busting the balloon.
In summary, there are a few ways to increase the length of time a balloon floats, but there is no way to keep it floating forever. The pores in the materials that balloons are made from are larger than the particles of Helium or air inside the balloon, so the balloon will eventually deflate.