What is the difference between a hydrogen filled balloon and an air filled balloon moving in air?
The main difference between a hydrogen-filled balloon and an air-filled balloon moving in air lies in the composition of the gases inside the balloons.
When it comes to buoyancy, both types of balloons rely on the principle of buoyant force, which states that an object will float in a fluid (such as air) if it is less dense than the fluid. In this case, the density of the gas inside the balloon determines whether it will rise or fall in the surrounding air.
First, let's consider an air-filled balloon. It is typically filled with normal air, which consists primarily of nitrogen, oxygen, and traces of other gases. The average density of air at sea level is about 1.2 kg/m³. The air inside the balloon has a similar density to the air outside, so the buoyant force acting on the balloon is relatively low. As a result, the balloon tends to have neutral buoyancy and remains at a constant altitude.
On the other hand, a hydrogen-filled balloon contains hydrogen gas, which is much lighter than air. Hydrogen gas has a density of about 0.09 kg/m³, roughly one-eighth of the density of air. The low density of the gas inside the balloon creates a significant difference between the density of the balloon and that of the surrounding air. Consequently, the buoyant force acting on the balloon is much higher than in the case of an air-filled balloon. This strong upward force causes the hydrogen-filled balloon to rise rapidly in the air.
It's vital to note that while hydrogen is highly buoyant, it is also highly flammable and poses safety risks, which is why helium is often used instead for commercial purposes, such as filling party balloons or blimps.
To summarize, the primary difference between a hydrogen-filled balloon and an air-filled balloon moving in air is the density of the gas inside. The lighter gas in the hydrogen-filled balloon results in a much higher buoyant force, causing it to rise rapidly, whereas the air-filled balloon tends to have neutral buoyancy and remains at a constant altitude.