Temperature, Pressure and Volume
December 13th, 2011It is a fact I quickly learned when doing balloons outside in the summer. A balloon left in the sun will eventually pop. While there are probably multiple things that lead the balloon to pop, I think a big issue is the increase in volume of the air trapped inside the balloon as it heats up in the sunlight. Eventually, it will expand enough to pop the balloon.
You don’t need to have a complete understanding of Thermodynamics to understand that there is a relationship between temperature, pressure, and volume of a gas. When you trap a fixed amount of air inside a container then heat the air one of two things will happen. If the container is solid, like a glass jar, the pressure inside the container will increase. If the container is able to expand like a balloon, the volume of the air will increase. The opposite is also true. If you cool the air, the pressure will decrease or the volume will decrease.
Last winter, I made myself a balloon hat while working at a local restaurant. When I left, I decided to walk to a store on the opposite side of the parking lot before heading home. It was a cold night and before I made it to the store, I noticed my hat was becoming limp and suspected that one of the balloons had popped. I took the balloon hat off and noticed it was much smaller, but within a minute of walking into the warm store, the balloon hat returned to its former size. What had happened? I had made the balloon inside a warm building and then took it outside where the temperature was freezing cold. The air inside the balloons cooled off and caused the volume of air to decrease making the balloons shrink. Once I returned to a warmer location, the air inside the balloons was able to expand and inflate the balloons to their normal volume.
While it is an interesting effect, it is important to realize the impact that temperature will have on balloons. When doing balloons outside on a cool day, it is important to realize that if the kids take the balloons inside a warmer building that the air inside the balloons will expand and increase the chance of the balloon popping. If making balloons inside when it is cold outside, it is equally important to realize that the balloon will deflate a bit when the kids go outside.