Why won't it float?

[AntiThought]

I have spent some time trying to figure this out. A sufficiently light structure filled with Helium or Hydrogen will float into the atmosphere (think balloons).

 

The reason for this is Helium and Hydrogen are lighter than the air they displace so this lighter structure floats to the top of the area of higher density air around it.

 

So I was thinking that the only thing easily obtained that is lighter than Helium and Hydrogen is nothingness. So why then if you had a very light structure that has been vaccuum suctioned so that no air is inside will it not float as well?

 

This is the way I see it...

 

Weight of Structure + weight of helium/hydrogen = floating

Weight of structure+ weight of nothingness (although loghter than the above) = no floating

 

Any ideas?

[Saizou]

Vacuum should float the best but there's a little difference from other floating stuff. Helium and hydrogen are lighter than air and when they are in a balloon they are under pressure (this makes them denser but still less dense than air) so they keep the balloon expanded. You can't fill a balloon with vacuum, since you are practically sucking everything out of it. So to maintain volume of a balloon 'filled' with vacuum you'd need some kind of fixed support inside the balloon so it won't flatten and yet again it has to be strong enough to withstand the atmospheric pressure. This support is often heavier than the force of buoyancy can counter so it won't float. If you can make a light enough structure then it has to float. It all comes down to difference in densities and since vacuum has 0 density it can float in anything, but maintaining a volume of it is what makes vacuum hard to utilize.

[AntiThought]

Thank you that is exactly what I was hoping the answer was. Now time to start researching my materials.

[ajnl]

yea the atmospheric pressure is huge. So anything that can with hold that pressure, will be too heavy.

 

As far as materials go, composites are extremely light weight and strong. Depending on the kind of composite and how the fibers are aligned, you can get strengths in different directions. But I high doubt that there is a material that is light enough and strong enough to accomplish this... at least not here on earth.

[PHANTASM]

A giant buckyball one carbon atom thick all the way around would work nicely.

 

Don't know if anyone could make a buckyball that big.

[ajnl]

Ah, forgot about the buckyball :-P lol

[PwRz]

Fun fact: Saturn would float.

[JoeDirt]

You can use cavorite, but the only person that knows how to make was stranded on the moon. Mr. Bedford was getting the recepie on how to make cavorite, but Grand lunar decided to cut all ties to Earth and Dr.Cavor was cut mid sentence. Bumer

[Duckie]

Why won't it float? Thats what she said.

[Rabidraccoon]

I don't think that you would have a perfect vacuum. Yes, it would provide more lift than anything we have on earth. But if you removed some of the air it would create lift. A liter of air at sea level weighs approximately 1.25 grams. So if you had a 1 liter bottle that weighed less than 1.25 grams it would float. You'd have to find a balance between pressures of the outside air trying to get in versus lift need to overcome the weight of the container. Also, the higher the altitude the less you will have to overcome outside pressures. Humidity and local air pressure also have an effect. Maybe a Mylar coating over carbon nano-tube frame, released from Mt. Everest during a storm, with high humidity air. Unless I'm totally mistaken. In that case I'll just go back to playing in the sand box.

[Aleena7783]

That was very interesting I never thought in such a way. Given explanation was fantastic. To make that more simple,

 

Weight of Structure + weight of helium/hydrogen = floating

Weight of structure+ weight of nothingness (although loghter than the above) = no floating

 

here you only considering the weight. But you have to consider more on the volume as well as the pressure.

[AntiThought]

Yeah I was not fully thinking through the problem the day I posted this. I placed it here to see if others had done the thinking before I did it myself.

 

What I have discovered is, that at this time, the cost of creating such a structure currently outweighs the practicality of the potential uses. I have now moved on to a problem related to the "chemistry of electricity" as I like to call it.

[SickOne]

When theres "nothing" in a closed room , there also is nothing that would create an uplift

[Thomas]

If you were to create a vaccum in an object light enough to float it would collapse the object.....the tricky part is finding something that will keep form and be able to have a vaccum pump run in it without collapsing but be able to float on "nothingness"