If I have a steel canister of helium and a balloon attached to the valve. If the helium is in the canister, the assembly stays on the ground. If I let the gas into balloon it floats. Why?
There is no change to the amount of energy, the gas is de-pressurised from the canister to the balloon and the density inside the balloon changes, but the overall weight stays the same.q I should know, I just can’t figure out why exactly.
Thanks
In: Physics
You are really asking 2 different questions. Buoyancy is how much water/oil/etc. an object needs to displace, or push to the side to float instead of sinking.
Why the balloon floats when you put helium in it is altogether different.
Air surprisingly enough, has a weight to it. The air we breathe has several different gasses mixed in, that each weigh different amounts. Helium is much higher than the other gasses on the periodic table, meaning each molecule, or the smallest piece of helium, weighs less than every other gas that we breathe. So when you fill the balloon with helium it floats up until it reaches the point in the atmosphere where it floats on top of the other, heavier gasses.
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