why does fire burn upwards?

Answer 1

Heat rises?!!!!

Answer 2

Gravity.

When a fire burns, the hot air is less dense and thus rises. this creates a vacuum effect that pulls cooler air in from the sides, continuing to fuel the fire. The flame is just following the air currents generated by its own heat.

In space, a flame doesn't do this because air density doesn't force air to rise. In space a candle looks more like a sparkler because there is no direction where 'rising' has any relevance without gravity. The candle just pushes the flame away from its source fuel in all directions as the air expands.

Answer 3

Great Question! First of all in a fire, carbon is being formed (dust, smoke...). When this is heated, it gives of its own colour -just like copper flames would give out green, or methane goes blue. So we see the orangeness of a normal fire.

Now the reason why a fire rises is that heat rises: or in actual fact the hot air in the flame rises, carrying those particles of carbon with it as well. This is why it seems to rise, at least I think so anyway!

Answer 4

For the same reason that a cork floats on water... it has a lower density.
As a fire burns, the molecules of gases heat up and expand. This makes them less dense (the molecules are moving faster and push each other farther apart.) Thus the fire rises.

Answer 5

For the same reason a hot-air balloon rises. The hot gases of the flame weigh less per cubic centimeter than the surrounding cooler air and 'float' upwards due to buoyancy in a sea of air.

Answer 6

Because man is born to trouble. Because hot gas is less dense than cold. The hot gas is pushed up by the cooler surrounding it. Without that effect, fires would not work.

(Man is born to trouble as the sparks fly upward. Job 5:7)

Answer 7

because it generates hot gasses that rise above the colder gasses in the air around it

Answer 8

Because heat RISES.