Why does burning air in a hot air balloon cause the balloon to rise?

Question

heat transfer

Answer 1

Air is not flammable, so of course it does not "burn" in a hot-air balloon. The density, or weight per unit of volume, of air decreases as its temperature rises, just like any gas. A hot-air balloon is bouyant in the atmosphere because the air inside the balloon is hotter than the air outside, making the balloon lighter than the portion of the atmosphere that it displaces. Through the Archimedian principle of bouyancy, the balloon floats in the surrounding atmosphere.

The air is heated by a burner that is fueled with propane. The pilot adjusts the lifting power of the balloon by adjusting the amount of propane that is burned.

For much more information, diagrams, and explanations, do an internet search on "Archimedes' principle of bouyancy," or just on "bouyancy" for that matter, or on "hot air balloon."

Answer 2

Burning air in a hot air balloon causes the balloon to rise because, first of all, hot air rises, and, since this now hot air is trapped inside the balloon, the hot air still rises and causes the balloon to rise too. If there is enough hot air trapped inside the balloon, the balloon itself will rise off the ground and stay aloft until the air inside the balloon begins to cool to the temperature of the air outside the balloon. As the air inside the balloon cools and becomes the same as the air outside the balloon (heat can be conducted and escape through the balloon), the weight of the balloon causes it to descend back to the ground.

Now the question becomes, well, why does hot air rise? Hot air rises because an outside source of energy (heat) is applied to air and causes it (the molecules that the air is made of) to expand and move faster causing it to rise up from the cooler air around it that isn't as active because it contains less heat.

Answer 3

yet warm air rises, which isn't in basic terms why it floats, yet in addition why the air continues to be trapped interior the balloon. If there replace right into a hollow interior the real, it does not go everywhere. however the nice and comfy air is going up, not down, so it won't manage to go out the hollow on the backside.

Answer 4

because hot air is lighter than the usual atmosphere, when air temperature increases it becomes lighter that it goes up similar to the evaporation process where hot air goes up un the clowds to be condense there and romed into liquid that makes it rain.

when air is heated, it expands making the balloon rise as the air pressure expanding inside the baloon lifts it up

Answer 5

It doesn't. Heat rises and just takes the balloon with it for the ride.

Answer 6

Good answer endpov.

Other answerers: The fact that air is hot has absolutely nothing to do with an air molecules mass. When hot it has more energy and is therefore more able to move, thus moving away from molecules with less energy.

Answer 7

hot air rises