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
Buoyancy is a force pushing upwards opposite to gravity. The steel canister is being pushed up by the buoyancy of the helium inside, however the gravitation forced pushing it down is greater (because steel is heavy) so it stays on the ground.
When the helium is transferred to a balloon, the buoyancy force is greater than gravity because the balloon is very light and therefore it floats upwards.
The force of buoyancy is dictated by the mass of the object relative to the mass of the volume of material (like air or water) that it displaces. If the object displaced more mass than it itself has, then it moves upwards. In other words, if the overall density (mass divided by volume) of the object is less than the density of the medium (air, water, etc.) it’s in, it’ll float.
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