Helium Balloon 3D: Buoyancy & Slow Deflation

A real latex balloon floats because of genuine Archimedes buoyancy, and it slowly loses that lift because helium permeates through the rubber membrane far faster than ambient air can diffuse in to replace it. This 3D simulator computes both effects live from the balloon's size, latex thickness, initial helium purity and ambient temperature: release the tethered balloon to watch it rise on real net buoyant force, then sink back down over a time-compressed clock as Fickian diffusion depletes its helium and dilutes the gas inside with air, until buoyancy can no longer support the balloon's own weight.