| Author | Message | ||
     vocasla Unregistered guest |
I just had a funny thought (that isn't so funny at all). Could it be possible to make a ball that looks solid and silvery shiny, that is tightly filled with helium, and that the helium can never get out. Then try to make it so that it will just float like 1 or 2 meters in the air to give the illusion that it is permanently levitating and that it would be the ultimate anti-gravity ball. (through adjusting the amount of helium in the ball, or by adjusting the weight of the ball). Note that the ball has to be light enough not to drop and heavy enough not to float away into the sky. lol.  | ||
| Anonymous |
I'm afraid that wouldn't work. The reason balloons float with helium is that helium is less dense than the air(meaning it has less mass, or weighs less, per unit). But, when you compress the helium into the ball, it gets more dense, and therefore would not be less dense than the air around it and so would not float. The ball would actually be lighter without anything in it then when filled with compressed helium. | ||
| vocasla Unregistered guest |
sorry, i should have mentioned - the gas is NOT compressed. The ball is like a miniture version of a helium balloon that is gives the illusion to look like it is a solid ball. | ||
| vocasla Unregistered guest |
when i ment tightly filled, i ment to say that the helium is sealed welll enough so that it cannot diffuse. | ||
| AnotherAnonymous Unregistered guest |
You could perchance make an aluminum foil balloon. It should be light enough to float. To keep it hovering, the easiest method I've found is to have a differential temperature layer in the room. It would also leak. I think anything would leak helium, even high pressure cylinders do. An alternate method could be to half fill a room with xenon or sulfur hexafluoride and half with helium (would have to be air tight, no admissions!), then you could use a thicker walled sphere, titanium maybe. It would still need to be really thin. An alternate-alternate method is to levitate it with a stream of air. The Exploratorium in SF has a basket ball perpetually hovering about 5 feet over a traffic cone (apparently the perfect shape for directing the air). You can reach up and grab it, and put it back, and the air is not too loud or intrusive. It could work with a light metal ball. | ||
| vocasla Unregistered guest |
Thanks! the 2nd is a pretty cool idea, I could get like an air-tight glass tank and fill them with those gases (or i can simply try using different gases and other materials that i can get hold of and is cheap). then i might get something to levitate in the center with no additional input energy. (until all the gases have diffused over time.) Your last idea is nice, but requires energy to create the stream of air flow. I'll try that anyway however, maybe using a small silent fan and i can concentrate the air flow to levitate a lghtweight object - it may turn out to be really cool in the end! | ||
| AnotherAnonymous Unregistered guest |
Well, for a smaller scale, you could just paint a ping pong ball with chrome paint and use a hair dryer. Examples: http://www.scitoys.com/scitoys/scitoys/aero/aero.html http://www.stevespanglerscience.com/experiments/experiment_print.php?experimentId=00000037 http://littleshop.physics.colostate.edu/Bernoulli.html A fan directly under probably won't work too well as it makes an uneven stream of air that has spin. You could try a strong air source (like a hair dryer, or 12" fan) at a remote location and have the air stream piped in. | ||
| AnotherAnonymous Unregistered guest |
Just to see if it was doable, I hooked up a 12 volt computer case type fan (rather quiet and not very powerful) to a toilet paper tube, and then a paper towel tube, but was unable to levitate anything. I switched to a 2" diameter tube from a wrapping paper roll, about 15" long. With that I was able to levitate a small balloon with a .177 BB inside for ballast. It didn't float very high, looks very unstable, and spins at about 45-60rpm, but:     I am guessing with some experimentation you could get a silver painted pingpong ball to float with a similar setup. | ||
| vocasla Unregistered guest |
Wow, that looks pretty cool! Thanks! I've got an air ioniser filter that blows out lots of air, and maybe i can get hold of pingpongs to do the trick. | ||
| Alessandro Carcione (alessandro) New member Username: alessandro Post Number: 13 Registered: 2-2005 |
I once did the same thing with a small 12dc motor a small propeller blade and a veriable power supply, it stayed about 15cm from the fan at 5v 180ma and was very stable kept going for hours, and it was very quiet too | ||
| lysdexia Unregistered guest |
Just use a solar hot air balloon! duh! You don't need to worry about diffusion because the gas is replenishable. | ||
| Anonymous |
I did it with a vacuum cleaner and an ordinary balloon. Or: Fill an air-tight glass tank (big transparent balloon?) with carbon dioxide (molecular weight 44). The ball should be filled with plain air (average molecular weight 28.9). The gross lift will be: for a ball of 30 cm diameter: 9.5 g for a ball of 1 ft diameter: 0.35 ounces The height should be regulated by permanently adjusting the pressure in the glass tank because static adjustment of buoyancy is impossible. Or: Fill the ball with helium. The gross lift will be: for a ball of 30 cm diameter: 15.7 g for a ball of 1 ft diameter: 0.58 ounces Regulate the height using a remote control vertical oriented propeller | ||
| Alessandro Carcione (alessandro) New member Username: alessandro Post Number: 19 Registered: 2-2005 |
Thats good but check out my hovering ballon, it floats about 1m from the fan and does not have any weight of bb's inside it will stay fairly stable and rotates at about 60rpm for half and hour so far, I don't know how long it will go for by itself though, I'd leave it overnight but I am afraid the motor might overheat. If anyone wants more info just ask.  | ||
| Alessandro Carcione (alessandro) New member Username: alessandro Post Number: 20 Registered: 2-2005 |
PS: the other post I posted I was talking about an other experiment I was using a different motor this experiment is a new one | ||
| ABCinventor Unregistered guest |
Cool!!! Why wouldn't the balloon fly off??? i mean u used the propeller alone without any thing that can concentrate the air to flow in a narrow space. How did it do that???!!! Well anyway its cool!!!! | ||
| vocasla Unregistered guest |
alessandro, i have to admit, that is indeed very very impressive. ;) | ||
| Alessandro Carcione (alessandro) New member Username: alessandro Post Number: 24 Registered: 2-2005 |
I also tried using it with a small NiCad battery it floats way lower but the motor is practically inaudiable, here are the resluts, I also made a video Video:http://www.freewebs.com/sci-stuff/Dscf0022.avi  Ps: The ballon is pink because I ran out of other colours.(dang!) | ||
| AnotherAnonymous Unregistered guest |
Have you tried it with a pingpong ball, or something else rigid? | ||
| Alessandro Carcione (alessandro) New member Username: alessandro Post Number: 26 Registered: 2-2005 |
I need to get some ping pong balls first, when I do I will post the resluts. |
