What is buoyancy and how does it relate to balloons?
Buoyancy is the property of objects that make them float on water. In simple terms, whenever an object is lighter than water, for example, it is expected to float. For most experts, many of them prefer the term ‘density’ when speaking about buoyancy. When an object is considered denser over a particular liquid, then the object will be able to float in the liquid. In a basic comparison, the fluid in this example should have more density than the object. And in this case, the lighter object will literally be buoyed up making it float above the water.
When it comes to balloons, though, the principle behind buoyancy may also be applied. In order for balloons to be buoyed up and float in the air, they must have a lower density against the air. And the only way to do this is to fill balloons with helium. Helium is another element that has less density than atmospheric air, and using the principle of buoyancy, balloons that are filled with helium rather than standard, atmospheric air will be less dense. The less dense the balloons become, the likelihood of floating in the air also increases. This particular example can be simply understood when filling some balloons with helium and the others with standard, atmospheric air. Those filled with atmospheric air will basically fall to the ground because of the weight of the plastic or rubber and because of the similar density to the air around them. Meanwhile, the balloons filled with helium will be less dense and so will literally become lighter than the air surrounding them. This property will then help the balloons get ‘buoyed up’ or float in the air.
With the principle of buoyancy applicable to objects placed in the air or water, many people can easily understand it. People just have to bear in mind that the less dense and lighter objects will always have the tendency to be buoyed up by the heavier and denser object.