If one were able to create a “balloon” out of carbon nanotubes and evacuate the air inside, would it act like a helium balloon and be lighter-than-air? It is my understanding that the “lift” of a helium balloon is due to the gas inside creating more buoyancy than the weight of the balloon itself. So, if we could create a balloon out of a super-lightweight material that is structurally sound, but void of any gasses, it should create lift in our environment, correct?
In: Physics
Answer: the point is that the “balloon” would need to weigh less than the weight of the volume of air it displaced for it to float. That is what buoyancy means and why things float in a fluid (like air or water).
So it is POSSIBLE, but you need to displace some volume of air AND the contraption needs to weigh less than that air.
It might be easier to think about water. A cubic foot of water weighs 62 lbs. A cubic foot of polyethylene (milk bottle plastic) weighs about 53 lbs, so it floats in water.
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