Why a ballon filled with helium loses the gas? or "stops flying"?
476319
A simple answer would be that the balloon does not sufficiently prevent the helium from escaping. This can be seen if you keep the balloon around the house for a while. The "air tight" system is not so air tight as you think, and obviously some of the gases escape. If by "stops flying" you mean stops rising higher, the answer may be that the balloon has reached a great enough altitude that the pressure of the atmosphere has decreased to match the pressure of the helium contained in the balloon. This is why balloons do not continue to float infinitely off into space.
172574
AP Physics is phun, dont let anyone tell you otherwise.\n\nFirst, find the volume of the balloon.\nThe volume of a sphere = 4/3 pi * r^3\nyou are given the radius, so this should be no problem.\n\nOnce you know the volume of the balloon, find how much Helium and air it would take to fill it.\nYou could do this two ways, (the Physics way or the Chemistry way) either by using the molar masses of the gasses....or using the densities of the gasses, the density way is probably easier, but you either need to have those given to you or you can look them up and assume what temperature the experiement is taking place at.\nYou need to find the masses of each of the gasses.\n\nThe lifting force of the balloon will equal the difference in the upward and downward forces acting on it.  The downward force is the force of the Helium's weight, the upward for is the weight of the air that the balloon is displacing (we ignore the weight of the ballooon).\n\nIf you want to believe wikipedia,\nthe density of air at 20 degrees C = 1.204 kg/m^3,\n\none mole of Helium = 4.00 grams.\nAt STP 1 mole of Helium would have a volume of about 22.4 Liters.
345743
i know!\n\nas temperature decreases, volume decreases. its part of the kinetic molecular theory.\n\nthe gas particles move slower because they lose energy as temperature decreases so they don't exert as much force on the walls of the balloon, so the balloon shrinks.
899047
not so bad really. Eventually enough helium will leak out and the balloon will come down.\nThe balloon is so fragile I doubt it would hurt an airplane. \nMy only concern is what happens when the balloon comes down. Most of them are at least partially latex and that stuff takes a long time to break down. I do hope birds and other creatures don't get tangled in them, but I have never heard of such a thing.
297042
cbw sounds convincing but that answer is only half true. When the baloon is only half full there are not enough gas/air molecules to fill the space. The random bouncing of the molecules against the wall of the baloon will hold the wall out only when there are enough molecules to fill the baloon. If you add more molecules, the baloon will expand due to the increased force of more molecules hitting thw wall, but with the same energy each as before. Heat the gas/air molecules and the energy of each molecule uncreases and there is increased force on the wall.
706335
The density of helium is only one-seventh of the density of air at the same pressure, so when the balloon is stable, the other six-sevenths has to be accounted for by a combination of (i) the weight of the balloon fabric, and (ii) the tension in the balloon fabric keeping the helium at a higher pressure than the surrounding air.  There is no simple answer, but four miles would not surprise me.
53886
Since the air inside the balloon is heated, the molucules are more active and therefore spread out. The weight of the air inside the ballon is less than the weight of the air that the ballon displaces.
535624
PV=nRT\n\nas the air is heated the average kinetic energy of the molecules increases. ie P increases.But V is constant. so some gas molecules escape through the bottom. Hence the density decreases and becomes lesss than that of surrounding air.Thus the balloon rises.
10432
The balloon is filled with hot air by the burner.  The hot air inside the balloon rises because it is lighter than cold (or cooler air).  assuming you mean't a hot air balloon.\n\nNobody is sure about helium ballons because we always suck the helium out so we can talk weird.
336395
I'm not pretty sure about this but because of the low molecular weight, the attraction between molecules is little and therefore outside forces can easily scatter these molecules troughout space. This results in gas state rather than liquid or solid
595563
Yes, it will weigh less. Fill ANY container with lighter-than-air gas, and it will weigh less.\n\nException: If the gas is under high pressure, such as in a pressurized tank, the container will actually weigh MORE.\n\nReason: Gas is compressible. If helium were half the weight of normal air, then helium under twice the pressure will weigh the SAME AS normal air under normal pressure. So if the pressure on the helium were increased, the container will weigh MORE.
297952
The hotter air is, the faster the molecules are air move around, bashing into things.  That mass of moving molecules is what keeps a balloon inflated-its literally uncountable trillions of tiny molecules acting like tennis balls banging around.  Increase the heat, and those molecules go faster, and hit the surfaces harder. They also spread out more, which is why hor air is lighter than cold air...less density of molecules. You put a fire in a bottle, and the air molecules move faster, and get more dispersed.  It fills the balloon, because of this expansion of the air.  As it cools down, the molecules collapse in closer together and move more slowly, and thus the balloon collapses.
127330
In part this depends upon what the small balloon is made of.  The balloon rises because of the buoyancy created by the density of the helium being less than that of the air surrounding the balloon.  The density of the air is less as one goes up. \nFor a rubber or latex balloon, as the balloon goes up, it expands because the pressure in the balloon becomes greater than the pressure outside of the balloon.  Eventually the balloon will pop because of the pressure difference.  This seems to be at a height of about 10,000 meters.\nFor a heavy plastic balloon, such as one made of aluminized mylar, The height obtained is much less.  Some of these balloons will pop at heights between 1000 and 2400 meters, but many will just reach an equilibrium and float until the helium gas leaks (causing the balloon to come back down).
991569
Yes this is an important topic.\nthe amount is tiny really.\nwhy not try to blow up a balloon and never burst it then all th gas will be traped and not effect the environment\nx x x
1864
It would definitely depend on the gas used. Some gases are heavier than air and would fall istead of rise. Consider also the pressure inside the ballon. It may rupture with the decrease in atmospheric pressure.\nToo many variables to give you a proper answer.
24312
Depends on temp and pressure, but at room temp, avg. pressure, helium's a gas
954967
According to the news article that I read, there is a shortage of Helium because the manufacturing plants are off-line.  The shortage has nothing to do with the amount of Helium left to find.