what happens to helium-filled balloons when they fly away?
351878
They pop. The higher the altitude, the lower the atmospheric pressure outside the balloon. But the same amount of gas is still inside the balloon, and it wants to be the same pressure as the air outside the balloon. Thus, the gas inside expands and pops your balloon.
856659
Helium is a lighter gas than the nitrogen/oxygen that our atmosphere is composed of, so a helium balloon will naturally float up.  It pops because the gas inside the balloon expands as the balloon rises to higher altitudes where the air pressure is lower.
642246
In certain Nuclear reactions involving smaller nuclei from hydrogen to Iron, alpha particles will be released. These alpha particles are basically Helium nuclei. When these Helium nuclei are passed through an electron beam, they get converted to pure Helium gas.
687166
The air in the ball is less dense than the surrounding pool water so less dense things rise upwards like a balloon. Helium is lighter than the Oxygen/Nitrogen mix found in the atmosphere and it is exactly the same with the pool and the ball. And when you drop something in like a rock it sinks to the bottom because more dense objects fall through the more dense ones like rain. In a pool there's more water so it seems like the air is naturally on top but in rain there is more air so it's like a mix until the gravitational attraction/density problems are fixed.
116245
I am making the assumption that the balloon is inflated with helium.  The molecules of helium contract when they are cold and expand when they are hot.  So if you put the balloon in the refrigerator or outside on a winter day, it will become smaller.  Once you put the balloon back into a warm environment, it will expand back to it's original size.
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.
738177
density of helium balloon is less than density of air( with 1 atmosphere pressure) so it goes up(just like wood floating water).\nbut density of air decreases by decreasing pressure(i.e. increase altitude) so in a certain altitude, density of air becomes equal to density of balloon then balloon cease to go higher.\n\nto get more info you can search "archimedes principle"\n\nI'm afraid you can not explain that to your kid! better to buy him a new balloon !\n\nmy source : studies in university
388915
As the air pressure decreases around it, the air, if contained in a flexible enclosure, would expand, pushing the sides of the container outward. IE: a balloon getting bigger. But I'm not sure what you mean by a "parcel" of air.
950534
oxygen atoms are larger than helium atoms.\nThe helium leaches out of the balloon quicker than the oxygen.
1127230
No, it's a nice idea though. As the balloon rises the pressure outside it will drop causing the gas inside the balloon to expand until eventually the balloon will pop. Sorry to burst your bubble as it where; I love the idea of space being filled with these multi coloured balloons though :))
18325
actually, they will eventually float when gases are released after they die and they balloon up.
875588
For C, that would normally be true.\n\nFor D, the answer is 1.2X10^24 atoms.\n\nFor E, helium atoms escaped through effusion.
469382
depends on the time of day. During a hot day the air balloon would pop first because air heats up juch faster than water. at night the air balloon would actually shrink because the air in the balloon would contract because of the cold air.
170260
Space is not a perfect vacuum devoid of particles, atoms, or molecules, it is a partial vacuum.  It is just that the density of matter in space is so small that it doesn't apply pressure against the balloon. If the balloon pops, the air inside the balloon is dispersed at the molecular and atomic level since air is comprised mostly of molecules: O2, CO2, CH4
378440
carnival baloons reach a specific hieght at which they stop verical movement and start to float around losing gas and eventually coming down to earth. i dont know why hey stop movung up but my guess is that they stop when the thickness of air at that altitude is less than the density of helium.
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.
946246
Helium particles are very small, in fact they are the smallest free particles that normally exist in nature. Although the plastic your balloon is made out of can stop water and sand and marbles and various other materials that have large particles, helium is small enough to go through, so it leaks.\n\nNow, there are certain kinds of balloons which are made out of special plastics and leak hardly any helium at all. However they are more expensive than the standard, cheap, leaky ones.