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At which point does hydrogen stop rising even if a balloon would never pop? If hydrogen is the lightest gas would not all of it rise making the highest part of the atmosphere?

It is not homework.

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closed as off-topic by ACuriousMind, Gert, John Rennie, user36790, Wolpertinger Sep 3 '16 at 20:00

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Homework-like questions should ask about a specific physics concept and show some effort to work through the problem. We want our questions to be useful to the broader community, and to future users. See our meta site for more guidance on how to edit your question to make it better" – ACuriousMind, Gert, Community
If this question can be reworded to fit the rules in the help center, please edit the question.

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    $\begingroup$ I'm voting to close this question as off-topic because it shows insufficient prior research. $\endgroup$ – John Rennie Sep 3 '16 at 5:35
  • $\begingroup$ @JohnRennie, I agree. $\endgroup$ – David White Sep 3 '16 at 14:28
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    $\begingroup$ @Muze Go research buoyancy and density, two very important concepts for floating balloons. $\endgroup$ – Bill N Dec 23 '16 at 17:54
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The ballon will stop rising when the net force on it becomes zero, which means that the buoyancy cancels the ballon's weight (gravitational force acting on it). This will happen when the density of the gas filling the ballon equals the density of the surrounding air.

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    $\begingroup$ This is a very "hand-wavy" answer, and is probably incorrect. $\endgroup$ – David White Sep 2 '16 at 22:17
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    $\begingroup$ It was a hand wavy question. In fact, I'm waving my hands right now! :) $\endgroup$ – QuantumBrick Sep 2 '16 at 22:19
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    $\begingroup$ The surrounding air density must be greater than the density of the hydrogen in the balloon, because the associated buoyant force must support the weight of the hydrogen AND the weight of the balloon. In addition, the solar wind would heat any "loose" hydrogen to the point where it would escape the earth due to hydrogen molecules' high velocity, so the hydrogen in the balloon cannot exist with high atmosphere "air" that has the same density, because this condition requires the balloon to be floating in hydrogen. $\endgroup$ – David White Sep 3 '16 at 2:13
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    $\begingroup$ Your answer was also hand wavish, except for the fact that you considered solar winds (?). I also disagree with your last sentence: the difference in the materials does not prevent anything from floating. A ball floats in water and it's not made of water. Also, when I said "weight", I was referring to the whole ballon... And I think you're being too specific, maybe. In a word: we're both waving out hands, but it looks like you're waving them faster! $\endgroup$ – QuantumBrick Sep 3 '16 at 2:18
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    $\begingroup$ Let's leave that for the OP to decide :) I hope someone (you?) answer it thoroughly with Newton's second law, including the balloon's mass and some particle showers from the solar winds. I'll be your first up vote! ;) $\endgroup$ – QuantumBrick Sep 3 '16 at 3:07

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