Ah yes, the warmth of the fire after a long days hike, the sizzle and pop of burning wood on a summers night, and mountains of cinders glowing so bright.
And then, your lungs are suddenly filled with a thick acrid smoke and your eyes become blood-shot.
Have you ever been sitting around the campfire and it seems that no matter where you settle down with your chair, the smoke tends to follow you?
I was told that there was a reason for this. It had something to do with your body temperature creating a small vacuum around you, drawing the heat and smoke toward you.
Obviously, wind speed would have to be zero for this to be accurate.
So my question is: If there is no wind, will there be a difference in the direction of the majority of smoke rising off of a campfire if a person is present or not present around it? Will body size or temperature (or any other factors of an animal being near a small fire) draw smoke toward him or her?
Warm air rises; your body is typically warmer than the surrounding air, so the air warmed by your body heat rises in a column and is replaced by air flowing in from around you (in all directions), but this effect is very unlikely to be all that significant, especially in real-world conditions - where there is nearly always other movement of air.
We also can’t ignore that the fire itself is a source of heat - more heat than your body, so the rising column of air from that should be generating more draw than your body.
Probably more significant factors in the ‘smoke always blows in your face’ thing are:
-confirmation bias; you don’t tend to notice or remember all the times that smoke doesn’t annoyingly blow in your face.
-eddy effects - if the wind is blowing from behind your back, it will form vortices as the air flows around your body - the motion of some parts of these currents is retrograde, so it could cause the smoke to travel toward you.
If you ever get a chance to play with a schlerien (sp?) photography setup, or do a Foucault knife edge test on a telescope mirror, the convection currents are obvious. I observed that my dog lying on the floor between the knife edge and the mirror made testing impossible.
That said, the convection currents are quite slow, and I don’t think they have a lot to do with the fireside observations.
I think the big factors are: 10 seconds of breathing smoke seems much longer than 10 minutes of NOT breathing smoke, so if a breeze is shifting randomly, it is psychologically going to seem unfavorable more than not.
And “common sense” dictates that many people stand upwind of the fire to avoid the smoke. The wind then swirls around them, creating a mild depression that draws smoke towards them. They are shielding the fire from the breeze they want to use to carry smoke away.
The second factor can be mitigated by standing crosswind from the fire…which does nothing about the first factor.
The traditional Girl Scout joke is, “Smoke follows beauty,” as MaryEFoo said. (My wife was a camp counselor.)
A friend of mine fell asleep/passed out next to a campfire. He was wearing rubber overshoes over his running shoes, and when he woke up, the rubbers and his shoes were welded together at the toes.
In the north woods, there remain remnants of Indian lore, one of which is the presence of the “smoke turner.” This spirit is capricious and unpredictable, so there’s no need to fight him. You can’t outwit him. He is apparently a relative of the famous “portage turner,” who can make a portage an uphill path into another lake, and then, as you return, makes the very same portage up hill on the way back. I know I have experienced that. There are things we are not given to understand. whooooooooooooo xo, C.
