Why Does Gas Float Upward: Investigating Mass Difference

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Discussion Overview

The discussion revolves around the reasons why gas rises instead of falling towards the Earth, with a focus on the concept of mass difference and buoyancy. Participants explore various scenarios, including the behavior of different gases in relation to air and gravity.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants suggest that gases float upwards due to being lighter than air, using helium as an example of a gas that rises in air.
  • Others question the relationship between mass and buoyancy, arguing that mass is generally attracted to the Earth and should fall.
  • A comparison is made between a stone and a boat in water to illustrate differences in buoyancy despite both having mass.
  • One participant proposes a hypothetical scenario regarding a helium balloon on the moon, suggesting it would fall due to the lack of air.
  • Another participant emphasizes that things float because of differences in buoyancy, noting that without air, a helium balloon would not float.
  • Some contributions express frustration with the lack of understanding and encourage participants to think critically about the concepts being discussed.
  • A participant mentions that gas has low weight, contributing to its ability to float.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between mass, buoyancy, and the behavior of gases. There is no consensus on the explanations provided, and the discussion remains unresolved.

Contextual Notes

Some assumptions about the nature of gases and buoyancy are not fully explored, and the discussion includes hypothetical scenarios that may not account for all variables involved.

AstrophysicsX
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Why does gas float upwards instead of falling towards the Earth ? Is it a mass difference ?
 
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AstrophysicsX said:
Why does gas float upwards instead of falling towards the Earth ? Is it a mass difference ?
What kind of gas are you talking about?

If you have a balloon filled with the a gas that is lighter than air (eg. He - an atom of He is lighter than a molecule of N2/O2) the balloon will rise. But if it is filled with a gas that is heavier than air (eg. CO2), it sinks.

AM
 
Why does it being lighter than air have anything to do with it floating upwards. Isn't mass supposed to be attracted to the Earth, therefore falling?
 
When you drop a stone into a lake, it sinks. When you put a boat into a lake, it doesn't sink. Don't the stone and the boat both have mass? Why does one sink and the other float?
 
Another way to look at this might be:
Would a helium balloon rise or fall on the moon? Answer: It would fall.
 
But why ? Explain please.
 
AstrophysicsX said:
But why ? Explain please.

Things float because of differences in buoyancy. There is no air or any other gas on the moon (I think) so there's nothing for a helium filled balloon to float on or sink in. The force of gravity would slowly pull it down.
 
Last edited:
AstrophysicsX said:
But why ? Explain please.
People are trying to help you by making you think, rather than spoon feeding. Do you not know why boats don't sink? Can't you apply that to a balloon? Even if you aren't sure, answer questions with a guess. Exercising your brain makes it work better.
 
lolarogers said:
Yea. comparatively gas has low wait. that's why its floats.

Yeah, gas doesn't stick around too long...
 

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