If heat rises, why don't fires just float away?

CantGainWeight

4

Christianity 1-0 Atheists

Reply 1

ByronicHero

20

Well, I'm persuaded.

Praises be to Moses, Noah and amazing technicolour dreamcoats.

Truer words have never been spoken

Reply 5

ombtom

17

Fires do float away. This thread has opened my mind.

Good...question...

The mechanism responsible for the rising of hot air is flotation: Hot air is less dense than cold air and hence air pressure will exert an upwards force, in the same way air rises in water. Now if cold air was magically unaffected by gravity, then it would not be able to exert pressure on the hot air and thus it would not rise.The statement that "heat rises", by the way, is not universally true. Look at water. Here, it is the cold water that is less dense than warm water (at least in the temperature regime of importance to freezing). In winter, when water gets colder, the cold water raises to the top and eventually will freeze, while the water below remains liquid for the moment.

Reply 8

CantGainWeight

OP

4

Original post by GUMI

The mechanism responsible for the rising of hot air is flotation: Hot air is less dense than cold air and hence air pressure will exert an upwards force, in the same way air rises in water. Now if cold air was magically unaffected by gravity, then it would not be able to exert pressure on the hot air and thus it would not rise.The statement that "heat rises", by the way, is not universally true. Look at water. Here, it is the cold water that is less dense than warm water (at least in the temperature regime of importance to freezing). In winter, when water gets colder, the cold water raises to the top and eventually will freeze, while the water below remains liquid for the moment.

answer the question

if heat rises

why dont fires float away????

Original post by CantGainWeight

answer the question

if heat rises

why dont fires float away????

Fires do float away. A fire is a continual chemical reaction occurring down at the base of the fire where the fuel is combining with air. The bit that most people would call a fire - the glowing, orange, wavy bit - is the hot gases produced by that chemical reaction floating away because they are hotter than the surrounding air.

Reply 11

N-R-G

17

They do they are stars.

Reply 12

Fenneko

20

All it takes is a Google search.

Reply 13

Zargabaath

21

Original post by CantGainWeight

answer the question

if heat rises

why dont fires float away????

They do actually, the fire is quite literally just ions giving off energy as light. These ions have enough energy to overcome their weight (which is basically nothing) and they do "float" away.