Cracker question because helium balloons are actually a pretty controversial topic. Some people argue that they are harmful to the environment because on returning to Earth, animals mistake them ...
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Ukrainian weather balloons: Low-cost spy gadgets in the skyPreparing such a balloon involves a process that takes 15 minutes and a team of 2-3 people. Filled with helium, these balloons can stay airborne for days to weeks. Notably, a helium-filled ...
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