Question

suppose we have a burning candle in a closed box such that the box has enough oxygen to keep the flame burning ; now if we through this box under the effect of gravity will the candle inside the box remain burning .......???

Answer 1

yes

Answer 2

ya..

Answer 3

at the zero gravity. the candle will still burninng but at slower rate.

Answer 4

well i think "no" coz i think there can be air disturbence ie air turbulence as due to the collision of opposite moving molecules ie one moving up and one moving down due to the reaction from the upper wall of the surface and it will give rise to air disturbence due to witch burning candle will not remain lit

Answer 5

I don't know the exact answer , but I think it will continue burning. till all the oxygen gets used up.
remember Edison's experiment with filaments..........

Answer 6

Sachin what u mean by the effect of gravity? :)

Answer 7

I assume that you mean zero-G. This wikipedia article : http://en.wikipedia.org/wiki/Diffusion_flame has a picture of a candle flame in zero-G. This one is from International Space Station.

Here, the main difference is of convection. Under gravity, convection causes hot air to rise and be replaced by cold air. For a flame, this means that the burnt gases rise up. It gets replaced by cold air containing unburnt oxygen. Thus we get a reasonably sized flame. Convection also gives the flame a tear-drop shape.

However in zero-G, convection doesn't happen. Hot air doesn't rise and so the flame burns with a spherical shape. Since the hot burnt air is not removed, it will hang around the flame - threatening to extinguish the flame due to lack of unburnt oxygen. But then, the unburnt cold oxygen from the rest of the air slowly diffuses through the hot gas and reaches the flame. This sustains the flame - but very weakly.

Answer 8

Gokuldas..
So, its means that the candle will still burning?
The moving of the molecules will only result in reasonably sized flame.
not off the flame?

And, is it related to 'why the flame always going upright, not down?'

Answer 9

The flame will be sustained only if oxygen supply to flame is replenished. On Earth, under gravity, convection aids this replenishment. Burnt gases rise up, giving chance for cold oxygen-rich air to reach the flame.

The same convection gives the flame an upright tear-drop shape. So yes, it is related to 'flame always going upright, not down'.

However in zero-G, the burnt gases will remain around the flame. This will definitely kill the flame if it weren't for another phenomenon - diffusion. Oxygen will diffuse through the hot gas and reach the flame. However, this process is not as fast as convection in replenishing the oxygen supply. So the flame is much smaller.

Answer 10

ok thanks..