why does a hot air ballon rise????
554015
The common answer to this question for a hot air balloon is "hot air is lighter than cold air." What does this really mean?\nIt means that hot air is less dense than cold air. Remember that density equals mass divided by volume. The substance with a lower density will float on top of another with a greater density. When the air inside a hot air balloon is heated, molecular motion increases, and the volume of the balloon expands. Therefore, its density decreases. The balloon will float until the density of its gas equals the density of the surrounding air. The density of the air decreases as altitude increases; because of gravity; gas molecules are more sparse at higher elevations. The air is "thinner" at high altitudes. The pilot can increase his altitude by heating the gas inside the balloon, thus decreasing its density.
376885
The heat causes waves in the air that affect the passage of light becuase the density is different than the surrounding air.  Same happens if you look at the fron of an  air horn like at a football game. But it's the opposite, it's caused by extreme cold.
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.
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).
895329
When you hold a ball up in the air, it develops potential energy because gravity wants to pull it down.  As the ball is dropping, that potential energy became kinetic energy, but loses some energy because of friction with the air.  At impact more energy is lost to the ground via thermodynamics (heat loss) and deflection (strain energy transfer).  The ball bounces back up with the remaining energy.  Something like that, better to ask a physics professor in high school or college :)
412631
A balloon filled with hot air rises because of the force of buoyancy. That means the density of air inside is lesser than the surrounding air (because hot air expands thus density decreases) and thus there is an upthrust acting on the balloon. Now, if the surrounding air is at the same temperature then its density is same as that inside the balloon and so the balloon will not rise. But the balloon will not not remain at the same point. it will fall because of the weight of the rubber in it.\n    In case of exploration on other planets, firstly other planets have very low density of air in the atmosphere (most of them do not have any air) and secondly even then is one wants to use this one has to heat up the balloon to a temperature for which the density decreass lower than the surrounding. Hope this answers your question.
80665
well as they said, the ball falls faster  than the feather, not becuase its heavier, not that gravity is more on it. its because of the simple reason, air risistence. in vacum, where there is no air , itll take the same time for both to reach ground.
165769
As the heat of the sun--or anything else--causes air to rise, its radius of rotation changes; this change in radius would cause a change in the angular momentum, so to conserve the angular momentum of the particle, the rising air mass has to develop a small additional velocity (it turns out to be opposite the rotation of the earth) as rises.  Here, in the northern hemisphere, that air flow would go north and east.  Also, as the air moves north, the angular momentum changes--aggravating that easterly vector in the velocity.  Eventually, the air cools, and going down & back south causes more changes; oddly, and I can't recall the precise physics here, it still retains a major easterly vector.  Thus, because of the earth's spin, a particle of air that rises and falls in one of the large convection bands (living between the jet streams) will do a spiral--think a widely stretched spring, here.
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.
820312
Because air preasure is distributed evenly and in all directions. Notice that if you blow on a bubble it changes shape temporarily, but only as long as the preasure on it is from one side. After you stop blowing it returns to perfectly round.
1125056
Canadian researchers are doing this actually. The rocket is lifted up as high as the balloon will go and then it is launched at a slightly upward angle. It saves a great deal of fuel and money and they maintain that Human manned rockets can be launched this way.
248011
It's called superheating. I don't quite understand it myself.
19622
Depending on the volume of compressible air within, the weight and density of the ball material, the density of the water and the pressure on the ball, it will first keep wanting to go up until it is compressed so far that there is an equilibrium, i.e. nothing happens. When the pressure increases further, the ball might become heavier than the water and sink down - depending on the density of the material and its compressibility.
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 :))
127151
Hot air has molecules which are more active from the energy that they receive from heat and, therefore, tend to collide more often with other molecules than when the air is cool. When more collisions occur, more pressure will be built up. To maintain pressure in the surroundings, the molecules will move to a place with less pressure, and that is upwards. When the air cools, it will go down again and the cycle continues.
58327
Pressure goes up as temperature goes up.
1002501
simple answer: expands till you heat it enough, then it breaks apart. (The gas breaks apart at the molecular level)\n\nbetter answer:\n\nWhen you increase the temperature of a substance the molecules store the energy in different forms. Forms such as vibrations, stretches, and translational motion. As the temperature is put in the system the air will increase its molecular motions (vibrations, stretches, translations...) the air becomes hot and the molecules move much quicker due to absorbed thermal energy. If you heat it enough you will rip apart the molecules and possibly start seeing a purple plasma. You can do this easily with a high voltage teslacoil.\nIf the closing material is fragile enough you can cause a pop! \n\nAdditionally, when fluids are heated the oxygen is removed slowly thus reheating can lead to superheating.\n\nAs you heat gasses, depending on their stucture, you can begin different modes of motion and change the heat capacity.