Helium Balloons - How Do They Do That?

If you’re considering helium balloon advertising, chances are, you might be wondering how helium balloon actually works. Most of us have no problem acknowledging that certain items float in water. However, the idea of something floating in air is a little more difficult to wrap our minds around. The truth is, the same laws that apply to an object floating in water also applied to objects floating in the air.

Consider this; everyone remembers the scene from Jaws wherein the shark uses his strength to pull two massive floating barrels under the water. Moments later, the two barrels pop to the surface. Because the barrels were filled with air, when pulled under they responded just like a helium balloon…Air is lighter than water; therefore, the barrels rose to the surface when the shark let them go. Basically, the air in the barrels displaces the water. The weight of the bottle itself, as well as the air, weighs only about 1 gram. However, 1 L of water weighs around 1000 g, almost 2 1/2 pounds. Simple physics proves that the bottle will rise to the surface.

The same principle applies to your new advertising balloon. The technical term for this principle is called “buoyancy”. As it turns out, helium is much lighter than air. The ratio between air and helium is not as great as the ratio between water and air. But nonetheless, helium is lighter than air. Helium weighs around .1785 g per each liter. Nitrogen weighs 1.2506 g per each liter. Because the air we breathe is about 80% nitrogen, a good estimation for the weight of air is 1.2 g per liter. As you can see, simple math proves that helium weighs less than air. On top of that the material used to make balloons is also very light. Depending upon the balloon, the amount of helium used to fill it will have an effect on the rate at which it rises.

Because new balloons are void of air, they can be easily filled with helium (which is lighter than air), and can therefore displaced air in easily. In theory, a balloon that’s partially filled with air, and filled the rest of the way with helium, will hover (that is if the ratio of air to helium is balanced).Basically, when your giant helium balloon arrives, and you’re ready to fill it using your helium tank, you will be displacing the air around the balloon because the gas if the balloon is lighter than air that surrounds it. While it sounds very scientific, in reality it’s not. It’s just simple math.