[ExI] scieceblind

John Clark johnkclark at gmail.com
Fri Oct 13 19:09:08 UTC 2017


On Fri, Oct 13, 2017 at 1:20 PM, William Flynn Wallace <foozler83 at gmail.com>
wrote:

​> ​
> No one of any age should be insulted when someone tries to cure their
> ignorance.  I don't mind being ignorant.  It's not shameful to me.  I just
> enjoy not being ignorant any more, so I am thankful to all who help me.
>

​And that is a very enlightened attitude! ​

​> ​
> I still don't get some of it.  Say you take a less dense object and put it
> underwater.  Since it is less dense, does that mean that gravity pulls less
> on it?
>

​Yes.​



>
> ​> ​
> And why should the water exert less of an upward force than on something
> more dense
> ​ ​
> Or is it gravity?
>

​Gravity exerts less of a downward force on on something less dense than
water then it does on water, it would rise for the same reason a balloon
does.
​A bubble of air at atmospheric pressure is 784 times​ less dense than
water so it rises in water, but air is compressible and water is not, and
the pressure  increases by one atmosphere every 10 meters down in the ocean
you go, so at about 78,400 meters a underwater bubble of air would have the
same density as water and so would not rise, and any deeper than that and
air would be more dense than water and the air bubble would sink.

Only trouble is the sea is not 78,400 meters deep, at least not on this
planet, and long before that the air would diffuse into the water,  but you
get the idea.

​> ​
> If I were standing in a vacuum, would there be less holding me up since
> there is no air to exert an upward force on my body?
>

​In a the air when you step on your bathroom scale there is a gravitational
force pulling you down but there is also a less strong force from the air
pushing you up, so in a
vacuum the reading on the scale would be slightly higher.


By the way, Einstein says acceleration and gravity are the same thing, so
when a car accelerates it pushes you into your seat but when you put on the
brakes you're pulled toward the windshield, however if Einstein was right
then a helium balloon in a car​ should move in the opposite direction that
you do because it is less dense than the air in the car but you are not.
This video tests to see if that is really true:

https://www.youtube.com/watch?v=y8mzDvpKzfY

​John K Clark​







> If this is correct, I am beginning to get it, eh?
>
> bill w
>
> On Fri, Oct 13, 2017 at 11:40 AM, Mike Dougherty <msd001 at gmail.com> wrote:
>
>> On Fri, Oct 13, 2017 at 12:07 PM, Dylan Distasio <interzone at gmail.com>
>> wrote:
>>
>>> I hope I'm not insulting by linking to an explanation, but I think it
>>> would help if you think about water displacement and how a less dense
>>> object floats in water.  It is the same exact principle when you have a
>>> less dense object (the helium balloon) compared to the air:
>>>
>>> http://science.howstuffworks.com/helium1.htm
>>>
>>>
>> Have we figured out how to fill a balloon with near-enough to nothing at
>> all to make a lighter than helium balloon?
>>
>> I know the structural requirement for a large volume of empty space is
>> considerable in Earth atmosphere.  I've been curious about the use of
>> aerogels with enough crush-resistance to make lighter-than air craft
>> literally filled with nothing - which would be cheaper and much safer than
>> the only [non-]thing with more lifting power than helium (see:
>> Hindenberg).  I mean sure, worse case scenario your balloon fills with
>> environmental air and crashes to the ground wouldn't exactly be a good time
>> but at least you wouldn't also be exploding and burning on the way to the
>> impact.
>>
>> I was also wondering if you could tether enough of these together to
>> encircle the globe, if you could hoist objects from this floating platform
>> and literally throw them into space.  Imagine a trebuchet floating on a
>> ship launching rocks lifted from the ocean floor, but the ship is floating
>> on the atmosphere and the rocks are aerodynamic sling bullets heading to
>> space.
>>
>> Well, enough thought experiment for now, I have to do actual work.
>>
>> _______________________________________________
>> extropy-chat mailing list
>> extropy-chat at lists.extropy.org
>> http://lists.extropy.org/mailman/listinfo.cgi/extropy-chat
>>
>>
>
> _______________________________________________
> extropy-chat mailing list
> extropy-chat at lists.extropy.org
> http://lists.extropy.org/mailman/listinfo.cgi/extropy-chat
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.extropy.org/pipermail/extropy-chat/attachments/20171013/7549f111/attachment.html>


More information about the extropy-chat mailing list