2006-12-12 06:25:45 · 8 answers · asked by shari s 1 in Science & Mathematics ➔ Engineering
http://science.howstuffworks.com/hot-air-balloon.htm
2006-12-12 06:28:03 · answer #1 · answered by Anonymous · 1⤊ 1⤋
It's all about diffusion and equilibrium. Hot air molecules are more "active" than their cooler brethren, Thus less hot air molecules can fit in the same space as cold air. so when you fill a balloon with hot air the air inside the balloon is less dense than the air outside, and the balloon rises.
Geek speak alert.
molecules like to be evenly spread with in any given space and if two molecule mix they eventually will reach a point at which the mixture is heterogeneous which is called equilibrium. Applying this to a balloon which has less dense air in a confined space which it cant escape. The lower density will provide lift to the balloon until it reached an altitude where the air density is identical to the balloon. The density of air naturally decreases with altitude, its a combination of gravity and the mass of air. when equilibrium is reached ascent stops and as the air in the balloon cools, density increases the balloon descends.
2006-12-12 14:50:36 · answer #2 · answered by Brian K² 6 · 0⤊ 1⤋
Hot air rises naturally. If enough hot air is held in a balloon it will lift the balloon as well.
2006-12-12 14:27:47 · answer #3 · answered by Tony B 6 · 1⤊ 1⤋
Hot air is less dense than cold air. Less dense means that it will become lighter for a fixed balloon volume. The lighter air of the balloon will float up through the more dense air outside the balloon just like a rubber ducky floats up through the water in your bath tub.
2006-12-12 14:32:18 · answer #4 · answered by Agent Smith 2 · 2⤊ 1⤋
Super heated air from a propane heater,is collected in the balloon,hot air rises,lifting the balloon.More heat the balloon rises,less heat the balloon declines.Walla !
2006-12-12 14:30:03 · answer #5 · answered by Anonymous · 0⤊ 2⤋
None of the answers above mentions BUOYANCY.
The hot air causes the balloon to rise, not because the air is hot and it wants to rise, but because it is displacing a sufficient volume of cooler, denser air for buoyancy to make the balloon rise, just like a cork floating on water by displacing enough water to offset the weight of the cork.
2006-12-12 14:38:17 · answer #6 · answered by www.HaysEngineering.com 4 · 0⤊ 2⤋
The heat applied by the burners to the air trapped inside the bag applies thermal energy to it and excites the air causing the air molicules to become less dence and move faster than the air outside the bag. This generates the lift required. This is also why warm air rises and cooler air sinks.
2006-12-12 14:39:40 · answer #7 · answered by S.A.M. Gunner 7212 6 · 0⤊ 2⤋
hot air that is increased to rise, and decreased to fall.
2006-12-12 14:28:16 · answer #8 · answered by St♥rmy Skye 6 · 0⤊ 2⤋