Re: [Phys-l] Space Balloon

[Joseph Bellina <jbellina@saintmarys.edu>]

You might ask the student what happens if you poke a hole in the  
bottom of a plastic cup full of water...and why he thinks that  
happens, and then ask what he think would happen in those two places.
Once you have established that the orbiting space craft is  
accelerating toward the center of the earth, you can replicate the  
situation by dropping the cup while the water is coming out of the  
hole and observing that the water stops coming out of the hole when  
the cup is accelerating towards the center of the earth.
Now you can start the students discussing what the balloon would do  
on earth and in the satellite.

Regarding deep space, you haven't described the motion of the  
spacecraft, so you can't answer the question.  Is it accelerating or  
not?

cheers

joe

Joseph J. Bellina, Jr. Ph.D.
Professor of Physics
Saint Mary's College
Notre Dame, IN 46556

On Feb 19, 2007, at 10:43 PM, thecraftyphantom@australia.edu wrote:

> Today as we were discussing gravitation and space, a student asked the
> following:
>
> On Earth a helium filled balloon rises because of bouyancy.  How  
> would the
> same helium filled ballon move in a spacecraft (eg space shuttle  
> cabin) if
> it was
>
>    a) in orbit around Earth
>    b) in "deep" space
>
> I would be interested in how you would answer this question.
>
> Regards
>
> Peter Craft
> Corowa High School
>
>
>
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